PC building and upgrade basics

Consider an upgrade first

A sluggish computer does not always need replacing. Desktops, and some laptops, let you replace or add memory and storage, and switching from a hard disk to an SSD alone often speeds up boot and app launches dramatically. First use the methods in the guide on slow computers to find which resource is short, then replace only that part; that gives the best value. If you would need to replace the processor or motherboard too, it is close to a whole new build, so compare the total cost.

Compatibility is half the job

Parts can look alike yet have different specifications, so they either will not fit or will not work once fitted. Memory of different generations (for example DDR4 and DDR5) cannot be swapped, and laptop and desktop memory differ in size. For storage, check the connection type, the physical size standard and whether the board supports it. A processor must match the board's socket, chipset and even firmware version. The most reliable reference is the motherboard or laptop maker's manual and support list. Do not rely only on 'compatible' labels on sales pages; check the manufacturer's documents yourself.

• Memory: generation, size (laptop or desktop), maximum capacity
• Storage: connection type, size standard, free slot
• Processor: socket, chipset, firmware support
• Graphics card: case length, power capacity, extra power connectors

Static is an invisible enemy

Static built up in your body can damage semiconductor parts even when it is too weak to feel at your fingertips. Before starting, touch grounded metal to discharge yourself, and wear an anti-static wrist strap if you can. Take extra care on carpet or in dry seasons. Hold parts by their edges without touching contacts or chips, and rest removed parts on the anti-static bag they came in. Cotton clothing builds up less static than wool. The lifestyle tips topic also has a guide to reducing static at home.

Power safety rules

Before working, always shut down the operating system properly, switch off the power and unplug the cable from the wall or the case. Then press the case's power button for a few seconds to drain charge left in the circuits. For a laptop, unplug the charger and, if the manual says so, disconnect the internal battery first. The large capacitors inside a power supply can hold a dangerous voltage even after it is unplugged, so never open one. If a battery is swollen, stop charging and using it, do not press or puncture it, and take it to a service centre. If you smell burning or see smoke, unplug immediately and stop using it.

• Shut down properly, switch off, unplug
• Press the power button to drain residual charge
• Never open the power supply
• Stop using a swollen battery and get it professionally repaired

Replacing memory and storage

For memory, open the latches at both ends of the slot, line up the notch on the module with the ridge in the slot, and press straight down until the latches click shut. If the notch does not line up it will not go in, so do not force it. When installing two modules, putting them in the slot pair the board manual recommends often enables dual-channel operation. When replacing storage, back up the old drive or copy it over with cloning software first. A new drive may need to be initialised in the operating system before it appears, and remember that initialising erases that drive.

Common building mistakes

The problem first-time builders hit most is no picture after powering on. The cause is usually memory not fully seated, an auxiliary power cable left unconnected, or the monitor cable plugged into the motherboard instead of the graphics card. Forgetting thermal material when fitting the processor cooler, or leaving its protective film on, is also common. Overtightening screws can bend the board or strip threads. When something goes wrong, the basic approach is to strip down to the minimum parts and reconnect them one at a time to narrow down the cause.

• Memory pushed in until the latches lock
• Processor and graphics card auxiliary power connected
• Cooler thermal material applied and protective film removed
• Monitor cable plugged into the graphics card

What to check afterwards

When you finish building or replacing parts, do not close the case straight away; power it on once to check everything is detected. Look in the firmware settings screen or the operating system's system information to confirm memory capacity and storage are recognised. If the processor temperature is abnormally high, recheck how the cooler is mounted. If all is well, close the case and tidy the cables. Tidy cabling looks better and also improves airflow inside, which reduces heat.

Cautions

Products differ in design and specifications, so this guide only describes a general order; always follow the manufacturer's manual for the actual work. Opening the case may affect the warranty, so check the terms first if it is still valid. Laptops often have parts soldered to the board or need special tools, which makes them harder than desktops. If you are unsure, or see any sign of an electrical problem, do not push on; hand it to a professional.