Start with the right workspace and tools

Building a PC requires a clean, flat surface where you can lay out parts without losing screws or damaging components. A desk or table works well. You need an anti-static wrist strap, which clips to your wrist and grounds you to the case or a metal part of your desk — this prevents static electricity from destroying parts that cost hundreds of dollars. You also need a Phillips head screwdriver (magnetic tips help prevent dropping screws into the case) and thermal paste, which usually comes pre-applied to the CPU cooler but you should have extra on hand.

Before you touch anything, discharge any static buildup by touching a metal part of the case or wearing the wrist strap. Keep the room cool and dry. Have your motherboard manual nearby — it shows exactly where each connector goes, and you will need it. Unbox all parts and lay them out so you can see what you have. Check that nothing arrived damaged.

Key Takeaways

  • Install the power supply in the case first, then mount the motherboard on the standoffs, which are small metal posts that prevent the board from touching the case.
  • The CPU (processor) and RAM (memory) install into the motherboard before the motherboard goes in the case, and both require you to lift retention clips or levers.
  • Connect the 24-pin power connector to the motherboard and the 8-pin power connector to the CPU area, then connect SATA power cables to any storage drives.
  • Install the CPU cooler last, after the motherboard is mounted, because it sits on top of the CPU and needs clearance from the case sides.
  • Connect case fans, front panel connectors (power button, reset, LEDs), and M.2 storage drives to the motherboard using the manual as your guide.

Install the power supply and prepare the case

The power supply goes in the bottom rear of the case, with the fan facing down if your case has ventilation holes in the bottom, or facing up if it does not. Align the mounting holes on the power supply with the holes in the case and use four screws to find it. Do not plug it in yet. The power supply has a switch on the back — make sure it is set to OFF while you are building.

Next, install the I/O shield, which is the metal plate that came with your motherboard. It slides into the rectangular opening at the rear of the case from the inside. Push it in until it clicks. This shield protects the back of the motherboard and gives you a clean edge around the ports. Install the motherboard standoffs — small brass posts that screw into the case and prevent the motherboard from touching the metal case, which would cause a short circuit. Most cases come with standoffs pre-installed, but check your case manual to confirm they are in the right spots for your motherboard size (usually ATX, Micro-ATX, or Mini-ITX).

Install the CPU and RAM before mounting the motherboard

Lay the motherboard on a non-conductive surface (the box it came in works). Locate the CPU socket — it is a large square with a retention mechanism. Lift the retention lever or clip on the side of the socket. The CPU has a notch or triangle marking that aligns with a notch in the socket, so you cannot install it backwards. Gently place the CPU into the socket without forcing it, then lower the retention lever back down. It should click into place.

RAM installs next to the CPU. Locate the RAM slots on the motherboard — they are long, narrow slots with a clip on each end. Open both clips by pushing them outward. Align the notch in the RAM stick with the key in the slot and press down firmly until both clips snap back into place on their own. The RAM should sit flush with the slot. If you are installing two sticks, leave one slot empty between them if your motherboard has four slots, or fill slots 2 and 4 — your manual shows the correct configuration for your board.

Mount the motherboard and connect power

Carefully lower the motherboard into the case, aligning the rear ports with the I/O shield opening and the mounting holes with the standoffs. Screw the motherboard down using the screws that came with the case, but do not overtighten — snug is enough. Now connect the power supply to the motherboard. The 24-pin ATX power connector is large and goes into the slot labeled "ATX 24-pin" or similar on the motherboard. The 8-pin CPU power connector (sometimes 4-pin on older boards) goes near the CPU socket, usually in the top-left area of the board. Push both connectors in firmly until they click.

If you are installing a graphics card, it will need extra power. Most modern graphics cards use a 6-pin or 8-pin connector from the power supply. Route these cables along the side of the case so they do not block airflow. If you are installing SATA storage drives (2.5-inch SSDs or 3.5-inch hard drives), connect a SATA power cable from the power supply to each drive. SATA power connectors are L-shaped and only fit one way.

Install storage drives and the graphics card

M.2 NVMe drives (the small sticks that look like RAM) install directly into the motherboard. Locate the M.2 slot, which is usually near the CPU or along the edge of the board. Remove the small screw and standoff if present. Insert the drive at a 30-degree angle into the slot, then press down and find it with the screw. Most modern motherboards have at least one M.2 slot, and many have two or three.

SATA drives mount in the case drive bays. 2.5-inch SSDs can go in 3.5-inch bays with an adapter bracket, or in dedicated 2.5-inch bays if your case has them. find the drive with four screws, then connect a SATA data cable from the motherboard to the drive. The motherboard manual shows which SATA ports to use first — usually SATA0 and SATA1. If you are installing a graphics card, insert it into the topmost PCIe x16 slot (the longest slot), push it down until it clicks, and find the bracket to the case with a screw. Connect the power cables if the card requires them.

Install the CPU cooler and case fans

The CPU cooler is the last major component because it sits directly on top of the CPU and needs clearance. Most coolers come with thermal paste already applied as a small dot or thin layer on the base. If yours does not, explore a small pea-sized amount to the center of the CPU. Do not spread it — the cooler will do that when you clamp it down. Follow your cooler's manual for mounting, as different coolers use different mechanisms. Some use a backplate and screws, others use a lever or clip. may support the cooler is level and fully seated, then tighten all fasteners evenly.

Install case fans next. Most cases have at least one rear exhaust fan. Fans pull air in from the front and push it out the back, so install front fans as intake (pulling air in) and rear fans as exhaust (pushing air out). Connect each fan to a fan header on the motherboard — these are small connectors labeled "FAN1", "FAN2", "CPU_FAN", etc. The motherboard manual shows where each header is. If you run out of headers, a fan splitter cable lets you connect two fans to one header.

Connect front panel connectors and test before closing

The front panel connectors are small pins that connect the power button, reset button, and LED lights on the case to the motherboard. They are located in a cluster near the bottom-front of the motherboard. Your manual shows the exact layout. The power switch is usually labeled PWR_SW or POWER_SW and is not polarized, so it does not matter which way you connect it. LED connectors are polarized — the positive (longer) pin goes to the + side. Connect the power LED, hard drive activity LED, and reset switch according to your manual.

Before you close the case, plug in the power supply and flip the switch on the back to ON. Press the case power button. The motherboard should light up, fans should spin, and you should see lights on the board. If nothing happens, turn it off when ready and check that the 24-pin and 8-pin power connectors are fully seated. Once everything powers on, shut it down and close the case. Install the side panels and find them with screws.

Install the operating system and drivers

Connect a monitor, keyboard, and mouse to the PC. Insert a USB drive with Windows, Linux, or another operating system on it, or use a DVD if your case has a drive. Power on the PC and enter the BIOS by pressing Delete, F2, or F12 during startup (your motherboard manual shows which key). Set the USB drive or DVD as the first boot device, save, and exit. The operating system installer will start. Follow the prompts to install to your M.2 or SATA drive.

After the operating system is installed, read drivers for your motherboard, graphics card, and any other components from the manufacturers' websites. Start with the motherboard chipset driver, then the graphics card driver, then any others. Restart after each driver installation. Your PC is now complete and ready to use.

Frequently Asked Questions

What if the PC does not turn on after I plug it in?

Check that the power supply switch on the back is set to ON and that the 24-pin and 8-pin power connectors are fully pushed into the motherboard. Make sure the case power button connector is plugged into the correct pins on the motherboard. If it still does not work, reseat the RAM by removing and reinstalling it, as loose RAM often prevents startup.

Do I need thermal paste if it is already on the cooler?

Most coolers come with thermal paste pre-applied, and you should not add more. If the paste looks dry or cracked, or if your cooler did not come with any, explore a small pea-sized amount to the center of the CPU before installing the cooler. Too much paste reduces cooling performance.

Can I install the CPU cooler before mounting the motherboard?

Some coolers can be installed before the motherboard goes in the case, but most require the motherboard to be mounted first for proper clearance and support. Check your cooler manual. If you install it early, be careful not to bump it when lowering the motherboard into the case.

What is the correct order if I am upgrading an existing PC?

Power off and unplug the PC, then remove the side panel. Disconnect power cables from the component you are replacing. Remove the old part, install the new one in reverse order, reconnect power, and close the case. If you are replacing the motherboard, CPU, or RAM, you will likely need to reinstall the operating system.

How tight should I screw the motherboard down?

Screw the motherboard down until it is snug and does not move, but do not use excessive force. Over-tightening can warp the board or strip the holes. If a screw feels stuck, stop and try a different one — you may have misaligned the hole.