Complete guide · from boxes to a running machine
Build your own pc
Everything fits one way only. That is the whole secret. Below is every step in order, with drawings of the connections people get wrong most often.
- 2 to 4 hours your first time
- You need one screwdriver
- 14 steps
Pick a part
Every block in this drawing comes back later as its own step. The case is lying on its side here with the panel off — exactly how you put it down to build.
What is inside a pc
Eight parts, that is all. The rest is optional. What follows each one is what to look at when buying — not the brand, but the detail that decides whether it works together.
-
Processor (cpu)
The calculating heart. It decides how quick your pc feels at everything that is not graphics: booting, browsing, compiling, crunching numbers.
check: the socket — AM5 (AMD) or LGA1700/1851 (Intel) has to match your motherboard exactly -
Motherboard
The board everything bolts onto and where all cables meet. It adds no speed of its own, but it decides what you can connect.
check: socket, size (ATX / micro-ATX / mini-ITX) and how many m.2 slots it has -
Memory (ram)
Working memory. The more programs and tabs at once, the more you need. 32 GB is the comfortable standard now, 16 GB the floor.
check: DDR5 does not fit a DDR4 board or the other way round — always buy a kit of two sticks -
Graphics card (gpu)
Draws the picture. For gaming, video and 3D it is the most expensive and most important part. For office work you can skip it if your processor has graphics built in.
check: length in mm against the room in your case, and how many watts it pulls -
Power supply (psu)
Turns wall power into what the parts want. This is the part you do not save money on: a bad one takes the rest with it when it dies.
check: wattage (gpu draw plus 250 W as a rule of thumb) and an 80 Plus Gold rating -
Storage (ssd)
Where Windows and your files live. An m.2 nvme stick is no bigger than a stick of gum and clicks straight onto the board — no cables.
check: 1 TB nvme is the sweet spot; older 2.5-inch ssds do need two cables -
Cooler
Carries the heat away from the processor. A good air cooler is quiet, cheap and lasts ten years. Liquid cooling looks better and handles heavy cpus better.
check: height in mm against your case, and whether the mounting kit covers your socket -
Case
The house. It decides how warm, how quiet and how easy to build this becomes. Buy one with room behind the motherboard tray for your cables.
check: does your board size fit, and does it already come with fans
Does it all fit together
This is where it goes wrong when it goes wrong — not while screwing things in, but in the shopping cart. Walk this list before you order anything. It remembers your ticks on this device.
Faster: drop your parts into a configurator like pcpartpicker.com. It shouts as soon as two things do not go together. Do not trust it blindly — it sometimes misses a required bios update.
Getting ready
Tools
A PH2 cross-head screwdriver, magnetic if you can. That is it. Handy but not needed: cutters for zip ties, a torch or your phone light, and a bowl for screws.
Where to work
A big table, no carpet, plenty of light. Keep the boxes within reach: screws, cables and manuals live in them. The motherboard manual is the only one that really matters — it shows exactly where the connectors sit on your board.
Static electricity
The risk is small but real. Two seconds of work removes it: before you pick up any part, touch a bare metal part of the case. Do it again if you got up in between or walked across a rug. Do not work in a wool jumper, and leave parts in their antistatic bags until you need them.
Keep the psu unplugged while you build. Plug it in only when everything is fixed down and you have checked the cables.
The order that works best
Processor, cooler, memory and ssd go onto the motherboard while it is still outside the case on the table — on the box it came in. Far more room, far better light. Only then does the whole thing go into the case.
Building, step by step
Fourteen steps in order. Nothing needs force: if something will not go, it is crooked or the wrong way round. Put it down and look again.
Motherboard on the table
Take the board out of its antistatic bag and lay it on the cardboard box it came in. That box is firm, insulating and exactly the right size. Put the manual next to it and find the diagram with all the connectors — you will need that page three times.
Fitting the processor
Open the socket: push the metal lever sideways and up, and the bracket swings open. On Intel there is a black plastic cover in it that pops off by itself when you close the bracket later — leave it alone.
Hold the processor by its edges, never by the underside. One corner has a small gold triangle. That triangle has to end up in the same corner as the triangle printed on the socket. Then let the cpu drop straight down into the socket — it falls in on its own. No pushing, no wiggling.
Close the bracket and press the lever back down. On Intel that feels alarmingly heavy. That is normal.
Bent pins are the most expensive mistake of the whole build. On AMD the pins are under the cpu, on Intel they are in the socket. Never drop anything into an open socket, and never close the bracket if the cpu is not lying flat.
Thermal paste and cooler
Is there already a grey layer on the bottom of your cooler? Then do nothing — that is pre-applied paste and it is fine. Only if the cooler is clean do you put paste on the middle of the processor yourself.
A blob the size of a pea is enough. No need to spread it: the pressure of the cooler does that for you. Too much is messy but not dangerous; too little costs you degrees.
Then mount the cooler. On an air cooler you tighten the screws crosswise: top left a few turns, bottom right a few turns, top right, bottom left, and round again until they stop. That way the pressure lands evenly on the processor. Hand tight is tight enough.
With liquid cooling you do the same with the pump block, and screw the radiator into the case — ideally at the top or the front, with the hoses pointing down.
Do not forget the fan plug: it goes on the header marked CPU_FAN. With liquid cooling the pump goes to AIO_PUMP or CPU_FAN and the radiator fans go to the normal fan headers.
Fitting the memory
Two sticks do not go side by side, they go every other slot. Count from the processor: slot 2 and slot 4. Get it wrong and the pc still starts, but your memory runs at half its speed. In the manual those slots are called A2 and B2.
Flip the clips open (on one side or both, that differs per board). Look at the notch in the bottom edge of the stick: it is not in the middle, so there is only one right way round. Press the stick straight down, one end first, then the other, until the clips click back audibly.
Fitting the ssd
Find the m.2 slot: a narrow, flat connector with a screw hole or clip about 8 cm away. If a metal heatsink covers it, unscrew that first and peel the plastic film off its underside.
Slide the ssd into the slot at about 30 degrees, until the gold contacts just disappear. Then press it flat and fix it with the screw or the clip. It will not stay down on its own — that is normal.
More than one m.2 slot? Use the top one, just below the processor: it usually hangs straight off the cpu and is the fastest. The manual also tells you whether a lower slot switches sata ports off.
Preparing the case
Take both side panels off — including the one at the back, because your cables run there later. Lay the case on its side with the motherboard tray facing up. Pull out every bag and piece of cardboard rattling around inside.
Now look at the metal tray the board will sit on. Small metal standoffs have to be screwed into it, exactly where the screw holes of your board are. Usually they are already in place for ATX; if they are not, you move them by hand into the right holes.
Did your motherboard come with a loose metal plate with cut-outs for the usb ports? That is the i/o shield. Clip it into the rectangular opening at the back of the case from the inside, with the text readable from outside. It goes in with a firm click. Modern boards have it attached already — then skip this.
Board into the case
Lower the board at an angle so the ports slide into the i/o shield first, then lay it flat on the standoffs. Push it gently towards the back until every screw hole sits exactly above a standoff.
Put one screw in the middle loosely first, so the board stops sliding. Then put the rest in and only tighten them all at the end. Hand tight again. You are screwing into thin metal, not wood.
Check that no metal edge of the case presses against the underside of the board, and that all ports poke neatly through the shield. Metal tabs from the shield must not sit inside a usb port.
Mounting the power supply
The psu goes in the bottom, fan facing down if there is a dust filter and an opening underneath the case (almost always). If the case stands on carpet or the opening is blocked, turn the fan upwards.
Slide it into place from the inside or the back and fix it with the four screws at the back of the case. If you have a modular psu, clip the cables you need into it now — reaching them later is much harder.
Which cables: the wide 24-pin, the 8-pin for the processor (sometimes two), and the power cable or cables for your graphics card. Sata power you take along if you have anything that draws from it: a 2.5-inch ssd or hard drive, a fan hub, a dvd drive or an led strip.
Only ever use the cables that came with your own psu. On the psu end the plugs look identical between brands but are wired differently. A cable from another power supply can burn your parts.
Fans and airflow
The principle is simple: cool air comes in at the front and the bottom, warm air leaves at the back and the top. Every fan has two arrows on it — one for the spin direction and one for the blow direction. You use the second one to decide how to mount it.
Make sure slightly more is blown in than out (three at the front, one at the back, for example). The case then sits under light pressure and pulls less dust in through the gaps.
The fan plugs go on the headers marked SYS_FAN or CHA_FAN. If your board has too few, use a splitter or the fan hub that is often glued to the back of the case. That hub itself runs off a sata power cable from the psu.
Fitting the graphics card
Find the top long pcie slot, straight below the cpu cooler. Count how many slots your card needs at the back (usually two or three) and unscrew exactly those cover plates at the back of the case. Keep the screws.
Flip open the clip at the end of the pcie slot. Hold the card with two hands, line it up straight above the slot, and press it down evenly until you hear the clip close. Then fix it with the screws you just took out.
Heavy card? Modern three-slot graphics cards sag if you only hold them at the back. If a support bracket came with your case or card, use it.
Connecting the power cables
Four connections, in this order. Every plug has a clip that clicks audibly; if you hear nothing, it is not all the way in.
- 24-pin into the wide connector on the right edge of the motherboard. This is the stiffest cable of the build — support the board with your other hand.
- 8-pin processor power into the connector at the top left, right next to the cooler. If your board has two (8+4 or 8+8), connect both if your psu can.
- Graphics card power into the top or the side of the card. Use a separate cable per plug; avoid the daisy-chained second end on cards above 300 watts.
- Sata power for everything else hanging off it: a 2.5-inch ssd or hard drive, a fan hub, a dvd drive, an led strip or a front display. One cable usually has three or four plugs in a row, so you can chain them.
Push the graphics card plug all the way in. With the new 12-pin plug (12V-2x6), half-seated is the reason one melts every now and then. It has to click and no gap may be visible. Do not bend the cable sharply within 3.5 cm of the plug.
The little cables from the case
This is the most annoying step and it takes five minutes. Out of the front of the case comes a bundle of thin wires with tiny plugs: POWER SW, RESET SW, POWER LED, HDD LED. They go onto a row of pins at the bottom right of the board, usually marked F_PANEL.
Polarity only matters for the two leds (the coloured wire is plus, white or black is minus). For the switches the direction makes no difference. Keep the motherboard manual next to you — every board lays these pins out slightly differently.
In the same corner you usually find the headers for the usb ports and the headphone jack on the front of your case. Those plugs are bigger and each has its own shape:
HD AUDIO— front headphone and microphone, bottom left on the board.USB 2.0/F_USB— a block of 9 pins with one pin missing.USB 3.0— big blue plug with a notch on the side.USB-C/Type-C— flat rectangular plug, fits one way only.
Tidying the cables and checking
Everything you do not need runs behind the motherboard, through the holes with the rubber grommets, and gets tied down there with the zip ties or velcro that came with the case. This is not a beauty contest: loose cables at the front block your airflow and can end up in a fan.
Then walk this list before you put power on it:
- The 24-pin and the 8-pin processor power are both fully seated.
- The cooler fan hangs off
CPU_FAN. - The graphics card is clicked into the slot and its power cable is all the way in.
- No cable touches a fan blade. Spin each one round with your finger.
- There is no loose screw lying on the motherboard. Tilt the case and listen.
- The protective film is off the bottom of the cooler. Seriously, this happens.
Ready for the first start
Leave the side panels off for now — the chance that something is wrong is small, but if it is, this saves you a lot of unscrewing. Stand the case up, connect your monitor cable to the graphics card (the ports low on the back), not to the motherboard. Add keyboard, mouse and the power lead.
Only then flip the switch on the psu to I.
Cable guide
Which plug comes from where and where it goes. If you have lost one, look it up here.
| Cable | From | To | How to spot it |
|---|---|---|---|
24-pin ATX | psu | right edge of the board | the widest and stiffest of them all |
8-pin EPS | psu | top left, next to the cooler | says CPU or EPS; square pins |
12V-2x6 / 8-pin PCIe | psu | graphics card | says PCIe or VGA — never swap with EPS |
SATA power | psu | 2.5-inch ssd, hdd, fan hub, dvd, led strip | flat, wide, L-shaped notch |
SATA data | motherboard | 2.5-inch ssd, hdd | narrow red or black lead with a latch |
CPU_FAN | cooler | board, next to the cooler | 4 pins with a plastic guide ridge |
F_PANEL | front of the case | bottom right of the board | loose wires with tiny plugs |
USB 3.0 header | front of the case | side of the board | thick blue plug with a side notch |
The first start
Press the power button. What you want to see: fans spinning, a logo on your screen, and a message that no boot drive was found. That last one is good news — it is alive.
Nothing at all? Skip ahead to it will not start. If all is well, tap Delete (sometimes F2) repeatedly during boot to get into the bios.
In the bios you do exactly four things
1 — turn on XMP or EXPO · otherwise your memory runs at 3600 instead of 6000
2 — check that your ssd and all memory are recognised
3 — see whether the cpu temperature stays under 50 °C at idle
4 — set the boot order to your Windows usb stick
save and exit: F10
XMP and EXPO are the same idea under two names (Intel and AMD): a stored profile that runs your memory at the speed you paid for. Without that switch it runs at the slow default. It is almost always on the first bios screen.
Will not boot after enabling XMP? Pull the power, hold the power button for 10 seconds and switch it back on. Most boards then fall back to default settings themselves. If that fails: the CLR_CMOS button or jumper on the board resets everything.
Windows and drivers
Making the install stick
On another pc: download the Media Creation Tool from microsoft.com, plug in an empty usb stick of 8 GB or more and let the tool build it. Takes about fifteen minutes.
Installing
Stick into the new pc, boot up, and pick your nvme ssd at the drive screen. If it has never been used it shows as one big block of unallocated space — select it and continue, Windows sorts the partitions out itself. You can skip the product key; you can activate later.
At the account screen: skipping the internet connection still works via Shift + F10 and then OOBE\BYPASSNRO, but Microsoft is closing that route off step by step. If it does not work, just create an account.
Drivers, in this order
- Chipset — from the support page of your exact motherboard model. This one first, always.
- Graphics card — straight from nvidia.com or amd.com, not from the disc in the box.
- Network and audio — usually handled by Windows Update; otherwise from the motherboard page too.
- Windows Update — run it two or three times until nothing new comes.
Checking that it holds up
Two tests, half an hour together:
- Memory: MemTest86 from usb, or the built-in Windows memory diagnostic. One error is one too many — then your memory is not seated properly or XMP has to come down.
- Heat: Cinebench or OCCT for twenty minutes with HWiNFO next to it. Under 90 °C on the processor is fine, 95 °C is the point where it throttles itself.
If everything stays stable, screw the side panels on and you are done. Look in the dust filters again in a few months.
It will not start
It is nearly always a cable. Look up the symptom.
Nothing at all — no light, no fan
Either power is missing or the button never arrives. Check in order: is the switch on the psu set to I, is the power lead firmly in the socket and in the psu, is the 24-pin fully seated?
If all that is fine, your POWER SW plug is probably on the wrong pins. Test it: pull the plug off and briefly touch the two POWER SW pins together with a screwdriver. If it starts then, you know enough.
Fans spin, but no picture
By far the most common one. In order of likelihood:
- Your monitor cable is in the motherboard instead of the graphics card.
- The 8-pin processor power is not connected. Look closely — this is the one most often forgotten.
- The memory is not deep enough. Press each stick in again until both clips click.
- The graphics card is not fully pressed into the slot.
- Your monitor is on the wrong input.
If nothing helps: take out all memory except one stick, put that in slot 2 and try again. Then try the other stick.
It starts for a second and dies, over and over
The classic short circuit or a dead psu. Check that the board touches the metal of the case nowhere and that no stray standoff sits under it where there is no screw hole.
One single restart on the very first boot is normal, by the way: the board is training the memory. On DDR5 that may even take a minute or two before you get a picture.
A light on the motherboard stays on
Those four leds (CPU, DRAM, VGA, BOOT) tell you exactly where it gets stuck. The light that stays on is the part it is hanging on.
CPU — processor power or the cpu itself. DRAM — reseat the memory. VGA — graphics card or its power cable. BOOT — no boot drive found, which is normal before Windows is on there.
The picture drops out while gaming, or it restarts by itself
Usually power or temperature. Use HWiNFO to see what the cpu and gpu do under load. If you are up against 95 °C, the cooler is not seated properly or there is no paste.
If everything stays cool, turn XMP/EXPO off in the bios. Unstable memory looks exactly like this. If it behaves then, your memory profile is too sharp for your particular combination.
The ssd does not show up during the Windows install
First check whether the bios sees it. If not: is the m.2 stick really screwed down flat, and are you using a slot that is not disabled by another slot or a sata port? That is in the manual in the m.2 chapter.