Meet the Computer — Hardware Mastery — Handout

Read this before or alongside the hands-on practice. This is reading material only — the module itself is where you plug real cables into real ports, sort real devices, compare real specifications and build a machine. 18 levels, 15 of them behind the module purchase.

The five jobs every piece of hardware does

Input — Carries information INTO the computer.
Output — Carries information OUT of the computer to you.
Processing — Does the actual thinking and calculating.
Storage — Holds information for later.
Communication — Connects this computer to other computers.

Some devices do two jobs at once — a touchscreen, a headset, an all-in-one printer. If you can place an unfamiliar device into one of these five, you can work out what it does.

Memory is not storage

RAM is the desk you work on: fast, and completely cleared the moment the power goes off. Storage (SSD, hard disk, flash drive) is the filing cabinet: slower, and it keeps everything with the power off.

Freezing when many things are open means not enough RAM. Slow to start and slow to open one thing means the storage — a hard disk rather than an SSD. Shops routinely call storage “memory”, so always ask two separate questions: how much RAM, and how much storage?

Ports at a glance — how to tell them apart

Power Socket	Three fat prongs in a D-shaped recess. Nothing else on the machine looks like it.
USB-A Port	A flat rectangle with a plastic tongue filling the top half — which is why it only goes in one way up.
USB-C Port	A small rounded oval, about a third the width of USB-A. There is no wrong way up.
HDMI Port	A wide, flat mouth with the bottom corners cut in — a squashed trapezium. Wider than USB-A and much wider than USB-C.
DisplayPort	Similar width to HDMI but with ONE corner squared off and the other cut — and it usually has a latch that clicks.
VGA Port	Blue, D-shaped, fifteen pin holes in three rows, and a thumbscrew each side.
Ethernet Port	A square-ish socket a little wider than a telephone socket, usually with two small lights above it.
Audio Out (green)	A small round hole. GREEN means out; pink means in.
Microphone In (pink)	The same size round hole as the green one — the colour is the only difference, and it is the whole difference.

If it does not go in easily, it is the wrong port or the wrong way up. Never force a connector — a broken socket on a motherboard is a repair, not a five-second fix.

Storage capacity, roughly

1,000 KB ≈ 1 MB · 1,000 MB ≈ 1 GB · 1,000 GB ≈ 1 TB

A page of typing is a few KB. A phone photo is 3–5 MB. An hour of video is 1–3 GB. A 64 GB flash drive holds roughly 16,000 photos.

Reading a specification

Core i5-1235U — i5 is the family; the 12 is the generation. Generation matters as much as the family.
Cores vs. GHz — cores are how many jobs at once; GHz is how fast each one runs. Match it to the shape of the work.
8 GB DDR4 — how much you can have open at once. Ask whether it is upgradeable or soldered.
512 GB SSD — the type matters more than the number for how fast the machine feels.
1920 × 1080 — how many dots make the picture, not how big the screen is.
Integrated graphics — right for documents, browsing and video calls. A separate card is for games, video and design.

Troubleshooting quick reference

“No Signal” on the monitor — the monitor is working and receiving nothing. Check the picture cable and which video port it is in.
Completely dead, no lights or fans — no power reaching the machine. Wall switch, cable at both ends, the switch on the power supply.
No sound, picture fine — the plug is very likely in the pink microphone socket instead of the green one.
No internet on a wired network — the Ethernet cable. No lights by the port means nothing is arriving.
Beeps and a black screen at power-on — the firmware’s self-test reporting a hardware fault, most often memory that is not fully seated.
Random shutdowns under load — overheating, or a failing power supply.
Slow, hot and loud after a few years — dust in the fans and vents. The machine is slowing itself down to survive.
Forgets the date every start-up — the CMOS battery is flat.

Method: check the simplest and cheapest things first, and change one thing at a time — otherwise you cannot tell which change fixed it.

Caring for hardware

Blow dust out of vents and fans every few months. Never vacuum inside a machine — static.
Liquid: switch off, unplug, drain, and give it a day or more to dry. No hairdryer.
Surge protector everywhere; a UPS for anything holding work that matters.
Unplug by the plug, never by the cable. Do not wrap a charger tightly around its brick.
Clean screens with a dry microfibre cloth — never household glass cleaner.
Take the flash drive out before packing a laptop away, and lift from the base.

Scope note

This module covers the physical machine, and it ends the moment the machine is assembled and powered on. What happens after that — the self-test, the manufacturer’s logo, the loading screen, the login screen and the desktop — is the separate module “Turning It On — Startup, Login & Shutdown”. Networking beyond “this is the Ethernet port and this is what it is for” belongs to a later networking module, and technician-level work inside a machine (thermal paste, firmware flashing, board-level diagnosis) is deliberately named rather than simulated.

What Hardware Is

Level 1 — What Hardware Is

Hardware vs. software, and the five jobs every device does: input, output, processing, storage, communication.

Hardware is everything about a computer you can physically touch. Software is everything you cannot — the programs and the files. The simplest test there is: if you could drop it on your foot, it is hardware. Word is software; the screen you read Word on is hardware. A photograph is software; the memory card it sits on is hardware.
Every piece of hardware ever made is doing one of five jobs: taking information IN, sending information OUT, PROCESSING it, STORING it, or COMMUNICATING with other computers. This is the single most useful idea in the whole module. Once you can place a device into one of these five, you can work out what it does even if you have never seen one before — including devices that do not exist yet.
Those jobs run in a cycle. Information comes IN, the processor works on it, the result goes OUT, and storage keeps whatever should survive being switched off. Type a letter (input) → the processor works out which letter and where it goes → it appears on screen (output) → you save it (storage) → you email it (communication). Every task you will ever do on a computer is that same loop.
Start with the easy one. Drag the Keyboard into the bin that matches what it does.
Now the Monitor. Which bin?
The CPU — the chip that does the actual thinking. Which bin?
An SSD — where your saved files live. Which bin?
A Router. Which bin?
Two of these catch almost everybody out. A PRINTER feels like it is doing work, but it only ever receives — it is output. And RAM feels like storage, because it holds things. RAM does store, but only while the power is on. We will come back to that difference in Level 5, because it is the single most misunderstood idea in computer hardware.

Level 2 — Input, Output & Both

Which direction information travels, and the devices that do both jobs at once.

Some devices do BOTH jobs at once. A touchscreen shows you a picture and feels your finger. A headset plays sound and captures it. An all-in-one printer prints and scans. Recognising a “both” device matters practically: it needs the machine to be set up for both directions. A headset that plays sound but is not selected as the microphone is the single most common cause of “they cannot hear me” on a video call.
Drag the Touchscreen into the right bin. There are only three bins now: Input, Output, and Both.
A Headset — earpieces and a microphone on one band. Which bin?
An All-in-One Printer, which prints and scans. Which bin?
Be careful: “it has a cable going both ways” does not make a device Both. What matters is whether INFORMATION travels both ways. A monitor's cable carries data one way — into the monitor. A printer's cable does carry a little information back (ink levels, “I am out of paper”), but its job is still output. A device is Both only when it genuinely does two jobs, like scanning as well as printing.

Level 3 — The Desktop Setup, Part by Part

Every part of a real desk: system unit, monitor, keyboard, mouse, speakers, webcam, printer, UPS.

Here is a complete desktop setup. Everything on this desk is hardware, and every single item plugs into the one box that is actually the computer. Click any part to hear what it is. From this level on you are working on real diagrams, not lists.
Click the SYSTEM UNIT — the box that is genuinely the computer, holding the processor, the memory and the storage.
Click the MONITOR — the output device that shows you what the computer is doing.
Click the KEYBOARD.
Click the MOUSE.
Click the POWER BUTTON on the front of the system unit.
Click the FRONT USB PORTS — the same USB sockets as the back, brought to the front for things you plug in and pull out often.
Click the SPEAKERS.
Click the WEBCAM.
Click the PRINTER.
Click the UPS — the battery backup everything plugs into, so a power cut becomes a few quiet minutes rather than a lost document.
Click the OPTICAL DRIVE — the CD/DVD tray. Increasingly rare, because software and films now arrive over the internet.
This is a DESKTOP: separate parts, each replaceable on its own, staying in one place. A LAPTOP is the same five jobs folded into one case that runs on a battery. Neither is better. A desktop gives more machine for the money and is far cheaper to repair, because any single part can be swapped. A laptop gives you the machine anywhere, and pays for that in price and in repair cost. Level 10 covers laptop hardware properly.

Inside the System Unit

Level 4 — Inside the Tower: Board & Processor (paid level)

The motherboard, the CPU, cooling, expansion slots, firmware and the CMOS battery.

The side panel is off. This is what has been inside the box the whole time. Knowing what is in here is not about becoming a technician. It is about being able to understand a specification, judge a repair quote, and say something more useful than “it is broken” when something goes wrong.
Before anyone opens a real machine: shut it down, unplug it from the wall, and touch the bare metal of the case to discharge static from your hands. Static electricity you cannot even feel can destroy a chip. This module teaches you what the parts are and what they do — actually fitting a processor and applying thermal paste is a technician's job, and we say so rather than pretending a simulation makes you one.
Click the MOTHERBOARD — the big circuit board every other part plugs into.
Click the CPU — the processor, the actual brain of the machine.
Click the CPU COOLER — the metal heatsink and fan clamped onto the processor.
A processor's specification has two headline numbers. CORES is how many pieces of work it can do side by side. GIGAHERTZ (GHz) is how fast each core works. An i5 with 6 cores at 2.4 GHz and an i3 with 2 cores at 3.6 GHz are not simply “slower” and “faster”. For work that splits up — video editing, rendering, many programs at once — more cores wins. For work that cannot split, the higher GHz wins. Level 12 goes into reading these properly.
The two names you will see on almost every machine sold are Intel (Core i3, i5, i7, i9) and AMD (Ryzen 3, 5, 7, 9). The number after the name is the family, not the speed. Roughly: 3 is entry level, 5 is the sensible everyday choice, 7 and 9 are for heavy work. But an i7 from eight years ago can be slower than an i5 from this year — so always check the generation, not just the badge.
Click the EXPANSION SLOT (PCIe) — the long slot where extra cards are added.
Click the SATA PORTS — where a drive's data cable plugs into the motherboard.
Click the CMOS BATTERY — the coin cell that keeps the clock running while the machine is unplugged.
Click the ROM / BIOS FIRMWARE chip — the permanent instructions that wake the hardware up and go looking for the operating system.

Level 5 — Memory: RAM, ROM & Firmware (paid level)

Why memory is not storage — the single most misunderstood idea in computer hardware.

This level is about the one distinction beginners get wrong more than any other: MEMORY is not STORAGE. Get this right and half of computer hardware suddenly makes sense — including why a machine with a huge hard disk can still be painfully slow, and why unsaved work vanishes in a power cut.
Click the RAM — the memory modules standing in the slots beside the processor.
Think of RAM as your DESK and storage as your FILING CABINET. Whatever you are working on right now is spread out on the desk, because that is where you can reach it fastest. A bigger desk means more things open at once without a struggle. But at the end of the day the desk is cleared completely — that is RAM losing everything the moment the power goes. Anything that must survive has to be filed away, which is what saving to storage is.
How much RAM is enough? 4 GB is painful today. 8 GB is the realistic minimum for comfortable work. 16 GB is right for anyone with many tabs and programs open, or doing design or video work. The symptom of not enough RAM is very specific: the machine is fine with one or two things open and grinds to a halt as you open more. If a machine is slow even doing ONE thing, the problem is usually the storage or the processor instead.
ROM is the opposite of RAM. Read-Only Memory keeps its contents with the power off — it holds the FIRMWARE, the built-in instructions the machine runs before it even knows an operating system exists. On a modern computer this is the BIOS or UEFI. When you press power, the firmware wakes the hardware, checks it is all present — that is the POST, the Power-On Self Test — and then hands over to whatever is on the drive. What happens AFTER that hand-over is the subject of the Startup, Login & Shutdown module.
Click the chip that holds that firmware and keeps it with the power off.

Level 6 — Storage Devices (paid level)

HDD vs. SSD, flash drives, memory cards, external drives, cloud storage, and what KB/MB/GB/TB mean.

Storage is where things live when the power is off. There are more kinds than most people realise, and they are genuinely different tools — not just different sizes. Choosing the wrong one costs real money: paying SSD prices for an archive nobody opens, or trying to work every day from a slow flash drive.
Click the HDD — the hard disk drive, built from spinning magnetic platters and a moving head.
Click the SSD — the solid state drive, with no moving parts at all.
SSD versus HDD, honestly: an SSD is roughly five times faster to read, silent, and survives being knocked. A hard disk is far cheaper per gigabyte and still the right answer for bulk storage. A hard disk has a physical head that must move to the right place on a spinning platter — that movement is the delay you feel every time a slow machine opens something. An SSD has nothing to move. This is why fitting an SSD to an old machine transforms it more than any other single upgrade.
Capacity runs in steps of roughly a thousand: 1,000 KB ≈ 1 MB, 1,000 MB ≈ 1 GB, 1,000 GB ≈ 1 TB. Useful anchors: a page of typing is a few KB. A photo from a phone is 3–5 MB. An hour of video is 1–3 GB. A 64 GB flash drive holds roughly 16,000 phone photos — or about 25 hours of video.
Portable storage: a FLASH DRIVE for carrying a few files, a MEMORY CARD for cameras and phones, an EXTERNAL DRIVE for backups and bulk, and CLOUD storage for reaching your files from any machine. Cloud storage is somebody else's computer, reached over the internet. It is superb for access from anywhere and for surviving a stolen laptop — and it is useless the moment the internet is down, which is a real consideration in much of Uganda. The honest answer is to use both: cloud for access, a physical drive for the backup you own.

Level 7 — Power, Cooling & Expansion (paid level)

The power supply, fans and heat, graphics cards, and why power quality is a hardware problem.

Three things in this box do no computing at all, and the machine is useless without every one of them: power, cooling, and the slots that let you add what the machine did not come with. These are also the parts most likely to be the real cause when a machine behaves strangely — and the parts most often blamed last.
Click the POWER SUPPLY UNIT — it converts 240V mains into the low voltages every component actually runs on.
Click the CASE FAN — cool air in, hot air out, for the whole case.
Click the CPU COOLER, which cools the processor specifically.
Click the GRAPHICS CARD — a processor specialised in drawing images.
Do you need a graphics card? Most people genuinely do not. Everyday machines use graphics built into the processor, which handles documents, browsing, video calls and full-HD video perfectly well. A separate card earns its money for gaming, video editing, 3D and design work, and AI. Buying one “to make the computer faster” for office work is money that would do far more good spent on RAM or an SSD.
Heat is the enemy of every component in this case. When a machine gets hot it does not fail immediately — it deliberately SLOWS ITSELF DOWN to survive, which is why an old, dusty machine feels sluggish. The cure is almost always dust. Fans and vents clog, airflow stops, temperatures climb, and the machine throttles. Blowing the dust out of a neglected tower can restore performance that no amount of software cleaning would.
In Uganda specifically, power quality is a hardware issue and not a small one. Surges and sudden cuts damage power supplies and corrupt whatever was being written to disk at that moment. A surge protector defends against spikes. A UPS defends against cuts as well, by giving you a battery-backed minute or two to save and shut down properly. For any machine holding work that matters, a UPS is not a luxury.

Outside the Machine

Level 8 — External Devices & Peripherals (paid level)

Printers, scanners, webcams, microphones, speakers, headsets, projectors — and which one solves which problem.

A peripheral is anything you add to the computer rather than something inside it. Almost every one of them is there to solve one specific problem. The useful skill is not naming them — it is knowing which one to reach for. This level works through the ones you will actually meet in an office, a school or a shop.
A SCANNER turns paper into a file. Drag it into the correct bin.
A PROJECTOR throws the screen onto a wall. Which bin?
A HEADSET. With only Input, Output and Both offered, which bin?
Headphones versus headset versus earphones: headphones play sound only; a headset adds a microphone; earphones are simply small headphones. For calls and online teaching this distinction is the whole point. A headset lets you be heard as well as hear, and it stops the microphone picking up the speakers — which is what causes echo on a call.
A projector needs three things to work: power, a picture cable (usually HDMI or VGA), and a dark enough room. Its lamp is a consumable — it dims with use and is expensive to replace. When a projector shows “No Signal”, it is almost always the same story as a monitor: the picture cable, or the laptop not having been told to send the picture out.
Two peripherals worth knowing in a Ugandan workplace specifically: a UPS, because power cuts are ordinary rather than exceptional, and a good surge protector, because voltage spikes destroy power supplies. Both are cheap next to the machine they protect, and both are routinely skipped until something expensive fails.

Level 9 — Ports & Connectors (paid level)

Plug real cables into real ports: USB-A, USB-C, HDMI, DisplayPort, VGA, Ethernet, audio and power.

This is the back of a system unit. Every socket here has a specific shape, and that shape exists so the wrong cable physically cannot go in. From here on you are not clicking pictures — you are picking up a cable and pushing it into a port. If the connector does not match, you will be told exactly what you were holding and exactly what the port was.
The single most important rule about ports: if it does not go in easily, it is the wrong port or the wrong way up. Never force a connector. Forcing bends pins and cracks sockets, and a broken port on a motherboard is a repair, not a five-second fix. Look at the shape, turn the plug over, try again gently.
Start with power. Drag the system unit's mains cable to the socket it belongs in.
Now the picture. Plug the HDMI cable into the port that carries picture AND sound to the monitor.
Plug the keyboard in. Its plug is USB-A — the rectangle with a plastic tongue in it.
Plug the Ethernet cable into the wired network port.
There are four ways to get a picture out of a computer, and you will meet all of them. HDMI carries picture and sound. DisplayPort does the same, preferred on high-end monitors. VGA is the old blue one — picture only, no sound. USB-C can carry video too on modern machines. In Ugandan offices and lecture halls VGA is still everywhere, which is exactly why a VGA-to-HDMI adapter lives in so many laptop bags.
On this bench, plug the VGA cable into the VGA port.
Now the DisplayPort cable into the DisplayPort socket.
USB-A is the flat rectangle that has been on every computer for twenty-five years. USB-C is the small reversible oval that is replacing it — same family, completely different shape, and there is no wrong way up. USB-C is not just a smaller plug. One USB-C cable can carry power, data and video at once, which is why some modern laptops charge, drive a monitor and connect a drive through a single port.
Plug the mouse into the SECOND USB-A port. Any USB-A port would work for a mouse — this one is to prove you can tell the two apart.
Now plug the USB-C cable into the USB-C port.
The two audio sockets are exactly the same size, so a plug will go happily into either. GREEN is sound going OUT to speakers or headphones. PINK is sound coming IN from a microphone. This is the one place on the back panel where the shape does NOT protect you from a mistake — only the colour does. It is also, for exactly that reason, one of the most common faults you will ever be asked to fix.
Plug the speakers into the correct audio socket.
Now plug the microphone into the correct audio socket.

Level 10 — Laptop Hardware (paid level)

Battery, charger, touchpad, built-in webcam, vents, hinge and laptop ports — and laptop vs. desktop honestly.

A laptop is the same five jobs as a desktop, folded into one case and given a battery. Everything you have learned still applies — it is just smaller, and joined together. What changes is the trade-off. Parts are harder or impossible to replace, repairs cost more, and every design decision is a fight for space. That is what you are paying for when you buy portability.
Click the SCREEN.
Click the BUILT-IN WEBCAM AND MICROPHONE.
Click the BUILT-IN KEYBOARD.
Click the TOUCHPAD — the built-in replacement for a mouse.
Click the BATTERY — the reason a laptop works with nothing plugged in.
Click the CHARGING PORT.
Click the COOLING VENTS.
Click the HINGE — the most-stressed mechanical part of any laptop.
Battery truth, because there is a great deal of nonsense about this. Modern laptop batteries do NOT need to be fully drained. Leaving a laptop plugged in all day is fine on any machine made in the last decade. What genuinely shortens a battery's life is heat, and being kept at 100% charge in a hot room for months. Batteries also simply wear out — after three or four years the same battery holds noticeably less. That is normal, not a fault.
The block on a laptop charger is a transformer converting mains to the low voltage the laptop needs. Chargers are not interchangeable — the voltage and the plug must both match. A cheap charger of the wrong voltage can genuinely destroy a laptop's board, and a fake one can be a fire risk. If the original dies, replace it with the manufacturer's specification, not simply whatever fits the hole.
Laptops have fewer ports because there is less room. That is why a USB hub or a docking station is such a common accessory — one cable to the laptop, and everything on the desk stays plugged into the dock. Modern thin laptops sometimes have nothing but USB-C, which is why adapters have become a standard part of a laptop bag.
On this laptop the charger is USB-C. Plug it into the charging port.
Connect the laptop to a projector. Which port takes the HDMI cable?
Slide the SD memory card from a camera into the right slot.

Level 11 — Printers in Depth (paid level)

Inkjet vs. laser, cartridges and toner, paper handling, connecting a printer, and fixing what usually goes wrong.

Printers deserve a level of their own because they are the peripheral that goes wrong most often, and the one whose real cost is hidden. The printer is rarely the expensive part. Over its life, what you spend on ink or toner will usually exceed what you paid for the machine.
Click the PAPER TRAY.
Click the OUTPUT TRAY, where finished pages come out.
Click the CARTRIDGE / TONER BAY — the part that runs out.
Click the CONTROL PANEL — the printer's own buttons and screen.
Click the SCANNER GLASS AND LID — what makes this an all-in-one.
Click the USB / NETWORK PORT — how the printer reaches the computer.
INKJET sprays liquid ink. Cheap to buy, excellent for photographs and colour, expensive per page, and the ink dries out if the printer sits unused for weeks. LASER fuses powdered toner with heat. More expensive to buy, far cheaper per page, much faster, and toner does not dry out. For any office printing volume of text, laser wins decisively. For occasional colour photographs at home, inkjet.
Ink and toner are consumables — planned running costs, not faults. A printer showing “low ink” is telling you to buy a cartridge, not that it is broken. Refilled and compatible cartridges are far cheaper and are widely used in Uganda. They are a genuine trade-off: real savings, against a higher chance of leaks, streaks, or the printer refusing to recognise the cartridge.
Paper jams have three usual causes: too much paper in the tray, damp or curled paper, and paper that was not fanned before loading so two sheets went in stuck together. When clearing a jam, pull the paper in the DIRECTION IT WAS TRAVELLING and pull slowly, so it does not tear and leave a scrap behind. A torn-off scrap inside the mechanism turns a one-minute job into a service call.
Connect the printer's mains cable.
Connect the printer directly to one computer with the printer cable.

Choosing, Caring, Fixing

Level 12 — Reading Specifications (paid level)

What “Core i5-1235U, 8 GB DDR4, 512 GB SSD, 1920×1080” actually means, line by line.

A specification is a shop's description of a machine, and it is written to be impressive rather than clear. This level teaches you to read one. Typical listing: “Intel Core i5-1235U, 8 GB DDR4, 512 GB SSD, 15.6″ FHD 1920×1080, Intel Iris Xe”. By the end of this level every one of those means something to you.
PROCESSOR — “Intel Core i5-1235U”. Core i5 is the family (i3 entry, i5 everyday, i7/i9 heavy work). The number after it is the generation: the “12” in 1235U means 12th generation. Generation matters as much as the family. A 12th-generation i5 comfortably beats an 8th-generation i7. When a listing gives only “Core i7” with no model number, that is usually because the model number is old.
MEMORY — “8 GB DDR4”. The 8 GB is how much you can have open at once. DDR4 is the generation of memory technology; DDR5 is newer and faster. Ask two questions the listing often hides: is it upgradeable later, and is it soldered to the board? On many thin laptops the RAM cannot ever be changed, so the number you buy is the number you keep for the machine's whole life.
STORAGE — “512 GB SSD”. The 512 GB is how much you can keep; SSD is the type, and the type matters more than the number for how fast the machine FEELS. A 256 GB SSD will feel faster than a 1 TB hard disk in every single thing you do, while holding a quarter as much. If a listing just says “1 TB” with no SSD or HDD, assume the slower hard disk — shops say SSD when it is one.
SCREEN — “15.6″ FHD 1920×1080”. 15.6 inches is measured corner to corner. 1920×1080 is how many dots make up the picture — more dots means sharper text, not a bigger screen. FHD (Full HD, 1920×1080) is the sensible standard. HD (1366×768) is noticeably coarser and cramped for real work. 4K (3840×2160) is superb and costs battery life.
GRAPHICS — “Intel Iris Xe” means the graphics are built into the processor, which is right for most people. A separate name like “NVIDIA RTX 4050” means a dedicated card. Integrated graphics handle documents, browsing, video calls and HD video perfectly. A dedicated card is for gaming, video editing, 3D and design. Paying for one you will not use is the most common way to overspend.

Level 13 — Choosing the Right Computer (paid level)

Real customers, real budgets: match the machine to the work rather than to the biggest number.

Buying well is one skill: match the machine to the WORK, not to the biggest numbers you can afford. Every scenario in this level is a real customer describing a real need. Read what they actually said — the deciding specification is usually mentioned in their own words, and it is often not the processor.
A method that works every time: (1) write down what the machine must actually DO, (2) find the one specification that decides it, (3) set a budget, (4) spend what is left on RAM and an SSD, in that order. RAM and storage type give more felt improvement per shilling than anything else for ordinary work. A faster processor is the least noticeable upgrade for someone whose complaint is that the machine is slow.

Level 14 — Caring for Hardware (paid level)

Dust, liquid, power protection, transport, screens and cables — the cheap habits that add years.

Hardware that is looked after lasts years longer, and almost all of the care is unglamorous and cheap. Nothing in this level requires a technician. It is the difference between a machine that is still working well in year five and one that is replaced in year three.
DUST is the number one enemy. It clogs fans and vents, airflow stops, temperatures climb, and the machine slows itself down to survive. Every few months: switch off, unplug, and blow the dust out of the vents and fans. Hold a fan still while blowing it, so it is not spun far faster than it was built for. Never vacuum inside a machine — vacuum cleaners generate static.
LIQUID is the number two enemy and the fastest killer. A drink over a desktop keyboard costs a keyboard. The same drink over a laptop can cost the whole machine. If it happens: switch off immediately, unplug, remove the battery if it comes out, turn it upside down to drain, and let it dry for a day or more before even thinking of switching it on. Do not use a hairdryer.
POWER. Use a surge protector everywhere and a UPS for anything holding work that matters. Shut down properly rather than pulling the plug. A machine cut off mid-write can corrupt whatever it was saving. This is also exactly why the Startup, Login & Shutdown module treats proper shutdown as a real skill rather than an obvious one.
TRANSPORT. Close a laptop before moving it, carry it in a padded bag, and never lift it by the screen — lift from the base. Take the flash drive out before packing the laptop away: a drive sticking out of the side is the classic way to snap a USB port clean off the board, which is a motherboard repair.
SCREENS. Clean with a dry microfibre cloth, or barely damp with water. Never household glass cleaner — the ammonia in it strips screen coatings permanently. Press gently. A modern screen is a stack of thin layers, and hard pressure leaves permanent marks.
CABLES. Unplug by the plug, never by pulling the cable, and do not wrap a charger cable tightly around its own brick. Both habits break the wires inside the insulation right where the cable meets the plug — the single most common way a working charger becomes a dead one.

Level 15 — Hardware Troubleshooting (paid level)

Diagnose a symptom and actually FIX it on the bench: no signal, no power, no sound, no network.

Troubleshooting hardware is a method, not a talent. Check the simplest and cheapest possibilities first, change ONE thing at a time, and let the symptom tell you where to look. In this level you will not just name the cause — you will fix several of these faults on a real bench. The machine in front of you is already wired up, and something about it is wrong.
The order that solves most faults: is it plugged in and switched on at both ends → is the cable in the right socket → is the cable damaged → swap the cable or the device for one known to work → only then suspect the expensive part. “Is it plugged in?” sounds like a joke. It is genuinely the single most common cause of a hardware fault, and skipping it is how people end up buying a monitor they never needed.
FAULT 1. The tower's power light is on and its fans are spinning, but the monitor says “No Signal”. Find and fix it on the bench.
FAULT 2. Completely dead — no lights, no fans, no beep. The wall socket is tested and working. Fix it.
FAULT 3. Video plays, picture is perfect, but there is no sound. The speakers are on and their own light is lit. Fix it.
FAULT 4. The machine works fine, but there is no internet. This office is wired — there is no Wi-Fi. Fix it.

Putting It All Together

Level 16 — Inside the Tower: Assembly (paid level)

Fit the power supply, processor, cooler, memory, drive, graphics card and case fan into an empty case.

An empty case and a table of components. You are going to put a machine together from the inside out. This is not a technician's course and it will not make you one — real assembly involves static precautions, thermal paste and torque you cannot learn from a screen, and we said so in Level 4. What it WILL do is fix, permanently, what each component is and where it belongs.
Real builds go in a sensible order: power supply first, because its cables must be routed behind everything; then processor and cooler onto the board; then memory; then drives; then expansion cards; then case fans. The bench will accept any order — but a component dropped on the wrong slot will tell you exactly why it does not go there.
Fit the POWER SUPPLY into the case.
Seat the CPU in its socket. In a real build it drops in one way only — a triangle on the chip lines up with a triangle on the socket, and it is never forced.
Mount the CPU COOLER on top of the processor.
Clip a RAM MODULE into the memory slots. Both clips must click shut — memory that is not fully seated is the classic reason a new build will not start.
Fit the SSD into the drive bay.
Seat the GRAPHICS CARD in the expansion slot.
Mount the CASE FAN so air actually moves through the case.
One thing a simulation can teach that a diagram cannot: a drive needs TWO connections — a data cable to the motherboard, and a power lead from the power supply. Forgetting the second one is the most common first-build mistake there is. The machine starts perfectly and simply cannot find the drive.

Level 17 — Comprehensive Hardware Exam (paid level)

Twenty tasks and questions drawn from every level in the module.

Everything from Levels 1 to 16, mixed and unannounced. Twenty questions and tasks, pass mark fifteen. Each task is a single attempt. Take your time — there is no clock.

Level 18 — Build a Computer & Power It On (paid level)

A desk of disconnected equipment. Connect every cable correctly, then switch the machine on.

Here is everything, disconnected: a system unit, a monitor, a keyboard, a mouse, speakers, a microphone, a network cable — and two cables this build does not need at all. Nothing is plugged in. You are going to connect all of it correctly and switch the machine on. Every connection is checked the moment you make it, and the checklist on the right shows what is still missing.
Three rules, all of which you already know. Match the SHAPE of the connector to the shape of the port. Never force anything. And remember that the two audio sockets are identical in size — only the colour tells them apart. Two of the cables on the desk are decoys: a VGA cable and a USB-C cable. Neither is wrong in general — they are simply not what this particular build needs, because the monitor here is connected by HDMI. Recognising a cable you do not need is as real a skill as recognising one you do.
Build it. Connect every cable to its correct port — power, picture, keyboard, mouse, network, speakers and microphone.
Everything is connected correctly. Press the POWER BUTTON on the front of the system unit. One press. Never hold it down — holding the power button cuts the power dead, which is a last resort and not a way to switch a computer on or off.
That is a working computer, built and running. The power light is on, the fans are turning, the power supply is feeding every component you fitted, and the monitor is live and connected. You assembled it from disconnected parts, chose the right cable for every port, ignored the two that did not belong, and started it — which is exactly what a technician does on the first day a machine arrives in an office.
What happens NEXT — the beep and the self-test, the manufacturer's logo, the loading indicators, the login screen and the desktop — is the subject of the next module: “Turning It On — Startup, Login & Shutdown”. That is deliberate, not an omission. This module is about the physical machine, and it ends the moment the physical machine comes to life. The startup module picks up from exactly this point: a correctly assembled computer with the power on, waiting to be booted and logged into.

Completing a level’s practical exam earns a Skill Badge — this is skill-building and self-assessment, not a certification or formal qualification.