How to Build a PC: A Beginner's Step-by-Step Guide

Building a PC is mostly careful plugging-in. If you can follow a recipe and you take your time, you can do it. Plan on an afternoon for a first build. This guide walks through the parts, how to check they work together, the assembly order, the first boot, and the mistakes that catch most first-timers.

The eight parts

• Processor (CPU): runs everything. Its socket (AM4, AM5, LGA1851) decides which motherboards fit.
• Motherboard: connects every part. It must match the CPU socket and the memory type (DDR4 or DDR5), and its size (ATX, mATX, ITX) must fit the case.
• Memory (RAM): 32GB in a two-stick kit is today's standard for gaming. DDR4 and DDR5 are not interchangeable.
• Graphics card (GPU): the biggest factor for frame rate in games. Check its length against the case.
• Storage: an NVMe SSD that screws into the motherboard's M.2 slot. 1TB is the practical minimum.
• Power supply (PSU): feeds everything. It needs enough wattage, and the right connectors, for your graphics card.
• CPU cooler: some CPUs include one in the box; many don't. Tower coolers must fit under the case's height limit.
• Case: holds it all. Good airflow matters more than looks.

You'll also need a Phillips #2 screwdriver, a USB stick of 16GB or more to install Windows, and a table with good light. Thermal paste is usually pre-applied on the cooler.

Check that everything fits

• CPU socket matches the motherboard socket.
• RAM type (DDR4 or DDR5) matches the motherboard.
• Motherboard size is supported by the case.
• Graphics card length is under the case's maximum GPU length.
• Cooler height is under the case's maximum cooler height (or the radiator size fits, for liquid coolers).
• Power supply wattage covers the CPU and graphics card with headroom, and it has the graphics card's power connector.
• The motherboard's BIOS supports your CPU out of the box, or the board can update its BIOS without a CPU (often called BIOS Flashback).

You don't have to check this by hand. The Build a PC page and the PC Wizard check every one of these rules as you pick parts.

Before you buy

• Match the memory kit to the board: its type (DDR4 or DDR5) and, on the board's page, the memory speeds it supports.
• Check the case has the front ports you want. If your board has a USB-C front header and you want a front USB-C port, the case has to have one.
• Check how many M.2 slots, SATA ports and fan headers the board has, and that they cover the drives and fans you plan to use.
• Check Wi-Fi. If the board has none and you aren't plugging in a cable, add a Wi-Fi card.
• Buy from a store with a return window, and test the parts soon after they arrive so a bad one can go back.

Which CPUs need a better cooler

A cooler that comes in the box (a stock cooler) is only meant for lower-power chips. It keeps a mid-range CPU at a safe temperature, but it is loud and runs hot under a long gaming session. As a rule, the more power a CPU draws, the more cooler it needs.

• Stock cooler is fine: entry and mid-range chips that ship with one, such as most Ryzen 5 and Core i5 models with no K or X3D in the name. Check the maker's page: it says whether a cooler is in the box.
• Buy a better air cooler: Ryzen 7 and Core i7 chips, and anything that includes a cooler but runs a long way above its power rating when you game or render. A $30 to $50 tower cooler is quieter and keeps the CPU boosting higher than a stock one.
• Buy a big tower cooler or a liquid cooler (AIO): K and KF Intel chips, Ryzen 9 chips, and X3D chips. These ship with no cooler at all. A dual-tower air cooler is the quiet, simple choice; an AIO with a 240 mm or 360 mm radiator moves more heat and suits very hot chips and small, cramped cases.

• Air cooler: check its height against the case's cooler limit, and that it clears your RAM.
• AIO: check the radiator size is supported at the top or front of the case, and that the pump block's mounting hardware fits your socket.
• Either way, compare the cooler's rated wattage (its TDP rating) with what your CPU draws under load, and leave headroom.

Power supply: enough watts, and the right plugs

A power supply has to cover the whole PC at its peak, and it has to have the right cables for your graphics card. Both matter: a PSU with enough watts but too few connectors can't run the card.

• Wattage: add up the graphics card and CPU gaming draw, then leave roughly 30% headroom. Check the graphics card maker's recommended PSU size, and never buy below it.
• Graphics card power plugs: a card can use none (slot power only), a 6-pin, an 8-pin, two or three 8-pin connectors, or the newer 12V-2x6 plug. Count the plugs on your card before you buy.
• Use one cable per plug. For a card with two or three 8-pin plugs, run a separate cable to each plug instead of one cable with two connectors on it, especially on high-power cards.
• A 12V-2x6 card needs a PSU with that native cable (ATX 3.x power supplies have it) or the adapter in the card's box. Push the plug in until it sits flush.
• CPU power: most boards need one or two 8-pin CPU (EPS) plugs. Count the ones on your board, and make sure the PSU has that many.
• SATA and Molex plugs: only needed for SATA drives, hard drives and some case fans and lighting. Check you have enough for the extras you plan to add.

Modular, semi-modular or non-modular? This only changes how many cables you have to hide:

• Fully modular: every cable unplugs. Cleanest builds, easiest cable routing, and you only plug in what you use. Best for small cases, glass-panel cases, and anyone who wants a tidy PC.
• Semi-modular: the 24-pin and CPU cables are fixed, the rest unplug. A good middle price for most builds.
• Non-modular: every cable is fixed. The cheapest option, and fine for a budget PC in a roomy case with the side panel on. The unused cables just need to be tucked away.

Spend the money on wattage, the right connectors and a trusted maker before you spend it on modular cables. Modular is a convenience, not a performance feature.

Storage: M.2, SATA SSDs and hard drives

• M.2 NVMe SSD: the norm today. It screws straight onto the motherboard, needs no cables, and is much faster than SATA drives. Put Windows and your games on it. Check how many M.2 slots your board has, and which are the fast ones.
• SATA SSD: still useful. It is cheaper than a fast NVMe drive for the same size, it is a good extra drive for games, and it is the answer when a board has no spare M.2 slot or only has older slots. It plugs in with a SATA data cable and a SATA power plug, and mounts inside the case.
• Hard drive (HDD): slow but cheap per terabyte. It is nice as a second drive for big libraries, videos and backups, and it is the route to a lot of space on a super-budget build. Don't use it as the only drive that Windows lives on.

A common mix is a 1TB to 2TB M.2 NVMe SSD for Windows and games, plus a larger SATA SSD or hard drive for everything else.

Choosing an operating system

Most gaming PCs run Windows 11, because nearly every PC game and every accessory program is made for it. Linux is a free alternative that works for a growing list of games. You can also have both on one PC.

• Windows 11 Home: about $140 retail from Microsoft, sold as an emailed digital license or on a USB drive. It's all most gamers need, and it supports up to 128GB of RAM.
• Windows 11 Pro: about $200 retail. It adds full BitLocker drive encryption, Hyper-V virtual machines, Windows Sandbox, the ability to accept Remote Desktop connections, and domain join. Pro supports up to 2TB of RAM. Pick it only if you need those features.
• Linux: free. Steam's Proton runs many Windows games on Linux, and the ProtonDB site rates how well each one runs. Games with kernel-level anti-cheat, such as Fortnite, Valorant and Warzone, don't run on Linux, and support changes often, so check the live anti-cheat tracker before you commit. There's also no official RGB lighting software, though OpenRGB covers many devices.
• Linux for gaming, in practice: SteamOS can now be installed on your own PC, but only with an AMD graphics card for now. Bazzite is a SteamOS-like system that ships NVIDIA drivers, so it suits NVIDIA owners.
• Dual-boot: Windows and Linux can share one PC, with a menu at startup to pick one. Back up first and keep Windows recovery media handy.
• No license yet: Windows installs without a key and runs with an "Activate Windows" watermark and locked personalization. That is outside Microsoft's license terms, so buy a license for a PC you plan to keep. A PC that shipped with Windows may activate on its own from a license stored on the motherboard.
• Windows 10: support ended on October 14, 2025. It still runs, but it no longer gets free security updates (Microsoft's paid extended updates for home users run until October 12, 2027). Install Windows 11 on a new build.

Prices above are typical retail prices. Check microsoft.com for today's price before you buy.

Step by step

• 1. Unbox the motherboard and set it on its box (not on carpet). Touch a metal part of the case now and then to discharge static.
• 2. Install the CPU. Lift the socket lever, line up the triangle marker on the CPU with the one on the socket, set it in gently with no pressure, and close the lever. On Intel and AM5 boards the pins are in the socket, so never touch it.
• 3. Install the M.2 SSD: remove the slot's heatsink or screw, slide the drive in at an angle, press it down and fix it in place.
• 4. Install the RAM. With two sticks, use the slots the manual calls for (usually the second and fourth from the CPU). Open the clips, line up the notch, and press firmly until the clips click.
• 5. Mount the cooler if it's a tower cooler or the stock cooler, following its manual. Peel off any plastic film on the cooler's base first. Plug the cooler fan into the CPU_FAN header.
• 6. Prepare the case: remove both side panels, check the standoffs match your board's screw holes, and fit the I/O shield if your board doesn't have one built in.
• 7. Lower the motherboard into the case, line up the rear ports with the I/O shield, and screw it to the standoffs.
• 8. Install the power supply (fan facing a vent), then route its cables to the back of the case.
• 9. Remove the expansion slot covers, push the graphics card into the top long PCIe slot until it clicks, and screw it to the case.
• 10. Connect the power: the wide 24-pin cable to the motherboard, the 8-pin CPU cable(s) at the top-left of the board, and the graphics card's power cable. Push each one in until it is fully seated.
• 11. Connect the case's front-panel cables (power button, USB, audio) using the motherboard manual's diagram, then plug in the case fans.
• 12. Tidy the cables so nothing touches a fan, then put the side panels back on.

First boot

• Plug the monitor into the graphics card, not the motherboard.
• Flip the power supply's switch on and press the power button. A first boot with new memory can sit on a black screen for a few minutes while the board trains the RAM. Give it time before you assume something is wrong.
• In the BIOS, check that it sees the CPU, all of the RAM, and the SSD. Turn on the memory's EXPO or XMP profile so it runs at its rated speed.
• Install Windows from a USB stick made on another computer with Microsoft's Media Creation Tool.
• Install the graphics driver from AMD, NVIDIA or Intel, then the chipset driver from the motherboard maker's support page.
• If the PC won't start, check the motherboard's debug lights (CPU, DRAM, VGA, BOOT). The one that stays lit points to the part to reseat.

BIOS updates and case fans

• BIOS update: newer CPUs sometimes need a newer BIOS than the one the board shipped with. Check the board's support page for your CPU. If it needs an update and the board has BIOS Flashback, you can update from a USB stick with no CPU installed. Otherwise you need a CPU the board already supports.
• Fan direction: the front and bottom fans pull cool air in (intake), and the rear and top fans push hot air out (exhaust). The side of the fan with the logo or frame spokes is usually the intake side, so check the arrow printed on the frame.
• Fan balance: at least one intake and one exhaust fan keeps air moving through the case. Leave the graphics card's own fans clear.

After the first boot: temperatures and returns

• Check temperatures in a free monitor such as HWiNFO or the CPU maker's own tool while you game for 15 minutes. If the CPU is hitting its maximum temperature (on the CPU maker's spec page), reseat the cooler and check it is mounted flat with the film removed.
• A loud fan that spins up and down at idle is usually a fan curve setting in the BIOS, not a fault.
• Run the PC hard for a few days while you're still inside the return window. If a part crashes the PC, random restarts or fails to be detected, test with another part, then send the bad one back.

Mistakes to avoid

• Forgetting the 8-pin CPU power cable at the top of the board. The PC won't start without it.
• Plugging the monitor into the motherboard instead of the graphics card.
• Leaving the plastic film on the cooler's base.
• Putting two RAM sticks in the wrong slots, or not pressing them in until both clips click.
• Not pushing the graphics card's power cable all the way in. A 12V-2x6 plug must sit fully flush.
• Mixing modular power supply cables from a different power supply. Pinouts differ between models, even from the same brand.
• Skipping EXPO or XMP, which leaves the memory running slower than you paid for.
• Rushing. If something needs force, stop and check the manual.