How to Build a PC from Scratch: Step-by-Step Beginners’ Guide

You don’t need to feel intimidated when learning how to build a PC. The process mostly involves screwing in the right screws and connecting the right cables, so as long as you’re careful with your components and take the proper safety precautions, you can build your own PC.

We’ve broken down the process into a series of easy-to-follow steps. From gathering your components to putting on the finishing touches, our guide will walk you through how to easily build a PC.

If you are already familiar with the overall process of building a PC, you can jump to a specific step using the list below:

Getting started

This guide is all about piecing components together to create a functional machine. If you haven’t selected and purchased all the required hardware, make sure you do that first. It’s also a good idea to purchase (or craft) your case last so you can make sure everything will fit inside it.

Have your parts? Good. Let’s build a computer!

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Before you dig in, ensure there’s a clean workspace with plenty of room to open boxes and put parts together. Hopefully, there’s already a pile in front of you. If not, our PC build guide can walk you through that process.

There are a couple of safety issues to discuss before we actually start ripping open those boxes.

Safety first

There’s an invisible risk when building a computer that can crush the most powerful system: Static electricity. The same force that lets you shock your friends when you wear wool socks can also fry components in a heartbeat. Fortunately, static is easy to all but eliminate with a few simple steps.

One simple solution is to purchase an anti-static wristband. One end wraps around your wrist, and the other clips somewhere on the computer case, keeping the wearer constantly grounded. Touching the case frequently with the PSU plugged in and powered off achieves the same effect.

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Apart from that, build your PC in a room with a bare floor — carpets generate a lot of static — and wear rubber-soled shoes rather than socks. Many components ship in anti-static bags, so leave them bagged until just before installation.

This guide serves as a general overview of the process, and the instructions packed with your parts may vary from our suggestions. When they do, default to the included instructions and use our guide as a road map for the overall project.

Opening the case

Preparing the case is the easy part. Instructions for the specific case you purchased should introduce you to its basic layout as well as list special instructions regarding component installation.

Lay down the case in your work area and remove the side panel. For most PC cases, this means the left-side panel when viewed from the front. This panel provides access to the case interior.

Also, remove anything that’s dangling inside the case. If it’s attached, push it aside. Many cases have permanent internal wiring that becomes problematic later on.

Before we start putting everything together, we’ll first install the power supply and then set the case aside for a few minutes.

Step 1: Install the power supply

The first component to make its way into the case should be the power supply (PSU). It is typically located at the rear of the case, usually in the bottom or top corner.

When in doubt, the slot is easily located by searching for a square opening with screw holes in at least two corners. The PSU sits in this opening with its power switch and a female socket facing out from the case’s back panel. Consult your case’s manual if you have trouble finding the proper location.

You can install the power supply with the fan facing up or down. In most computer cases, pointing the fan down is ideal. All you need to do is look at your case. If there’s space between the bottom and floor (and preferably a dust filter in between), install your power supply with the fan facing down. Most modern cases are built for this type of installation. If your case manual says something different, however, we recommend following that.

There are two main power supply variants: Standard and modular. There’s a hybrid semi-modular type too, but we don’t need to worry about that for now.

Modular PSUs have cables that detach from the main unit to avoid clutter. They’re ideal for smaller cases and neat freaks. If you have a modular PSU, it’s best to leave the cables out for now and run them as you install each additional component.

If the PSU’s cables don’t detach, carefully bundle them so they’re hanging out the case’s open side panel. This temporarily keeps them out of the way while we install the remaining components.

Step 2: Install the processor

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Next, prepare the motherboard by installing the CPU and RAM before fitting it in the case. They’re a lot easier to install now rather than after the motherboard resides in the system.

In fact, depending on your case and cooler, you may not be able to assemble your system with the motherboard already installed. That’s because many after-market coolers use a backplate to provide the tightest fit possible. It is, of course, attached to the back of the motherboard. You won’t be able to install it unless you have a case with a cut-out that aligns with the backplate’s location, a feature typically found only in high-end enclosures.

There are numerous pins on the CPU and motherboard, and bending any one of them could render that component kaput.

Carefully remove the motherboard from its anti-static bag and set it on a hard, flat, non-metal surface such as a wooden desk, or the top of the motherboard box itself. Also, make sure there are no s of dust or liquid nearby.

Even though installing a CPU is an easier task now than it was in previous years, it’s still one of the most precarious. There are numerous pins on the CPU and motherboard, and bending any one of them could render that component kaput.

That said, the process isn’t designed to be difficult, and as long as you follow the instructions clearly and keep an eye out to ensure the chip is fully seated before you clamp it in place, you’ll be fine. However, there are some subtle differences in the process depending on who made your CPU.

How to install an Intel processor

Instead of jutting from the processor, pins now reside in modern Intel sockets on motherboards, making CPU installation easy. This part of the socket is called the contact array. Absolutely do not bend or touch these pins!

The square metal bracket holding the CPU in place is the load plate, and it’s raised and lowered using the load lever. When clamped down, the end of the load lever tucks under a hook to keep everything in place. When you unbox your motherboard, the contact array will be covered with a piece of plastic. This plastic will pop out once you open the bracket, so wait to open it until you’re ready to install your processor.

First, open the load plate. Do this by gently pushing down on the load arm and moving it out sideways from under the hook, and then raising it up all the way. The hook’s lever action opens the plate, which you can easily flip up. At this point, the plastic piece will come loose. If it doesn’t pop out, gently remove it.

As shown above, the CPU itself should have a small half-circle notch on each side of the chip. With the contacts facing down, there should be only one direction where the notches line up with the notches in the socket. Pick up your processor by the sides, clamping it lightly between your fingertips. Here, you want to avoid touching the bottom of the processor.

With the processor in hand, line up the notches (or use the small gold triangle in the corner to line up the socket) and set the processor in. You don’t need to apply any force here. The processor should slot in without issues. Once it’s sitting in the socket, very gently press the side to make sure it’s slotted in. Again, very gently do this. You don’t want to move your processor. You want to make sure it’s in place.

Use the load arm on the side to lower the plate over the chip, then push down and re-clip the arm under the hook once again. This requires a fair amount of pressure, so make sure the chip is properly seated before pressing down.

Remember, the notches in the processor should align with those in the socket. If in doubt, start again and double-check.

How to install an AMD processor

Unlike Intel’s design, pins jut from AMD’s CPUs. These pins insert into holes embedded in the motherboard’s CPU socket. The load arm on the socket slightly shifts the holes underneath, gripping the pins on the processor when pressed all the way down.

If it isn’t already, raise the arm so that it’s pointing straight up, and then rests a little farther back. That ensures the holes for the pins are wide open.

Instead of using notches, correctly line up the processor in the slot using a triangle engraved in gold on one of the CPU’s corners. All you need to do is line that triangle up with a second triangle cut into the slot. Again, pick up the processor by the sides gently, avoiding the bottom.

Once the processor sits comfortably in the slot, simply press the arm down until it clicks into place and locks in. This last step can be intimidating since it requires a fair amount of pressure to lock in place.

Step 3: Install the RAM

System memory, or RAM, doesn’t require any careful goo placement or wires. There are just two important factors, assuming you’ve chosen compatible RAM: Direction and slot choice.

The direction is easy enough. Each memory stick has a notch in the contacts lining the bottom edge that lines up with a block in the motherboard’s memory slots. If you hold it just above the slot and the two line up, it’s facing the right direction. If it doesn’t line up, spin it 180 degrees.

Slot choice depends on a few factors, one of which is how you purchased RAM. If it’s just a single stick, install it in the A1 slot and move on with your life. A diagram in the motherboard’s manual should label the slots if it isn’t printed directly on the PCB.

However, you likely purchased two identical RAM sticks, a common package called a dual-channel configuration. The system can use both sticks as if they were a single block of RAM but accesses them individually, providing a modest boost to memory performance.

You should install these sticks in channels (slots) with matching colors, usually labeled A1 and B1, though sometimes A2 and B2 are preferable. Check your motherboard’s manual to confirm which are best for your system.

Now that we know the proper slot and direction, the next part is easy. Push the plastic wings at either end of the slot down and outward (some motherboards only have one) then place the stick in the slot sticking straight up. Push down firmly until the RAM clicks into the slot, and the plastic wings click back in and clamp the ends of the sticks.

We put together a more detailed guide for how to install RAM if you need additional information.

Step 4: Install the motherboard

Installing your packed motherboard is easy enough, but it can’t just sit in your case. Most modern cases have built-in, non-removable spacers between the back wall and motherboard, known as standoffs. They act as a ground for the motherboard while preventing the connections on the back from shorting.

Some cases have removable stand-offs you must manually install. They’re easy to identify because they look unusual — essentially screws that have another screw hole on top instead of the typical screwdriver notch. They’re usually copper or gold in color, making them easy to pick out.

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Your motherboard’s orientation depends on your case. At the back or the top, you’ll see a rectangular cut-out. This is for the motherboard’s I/O panel — the portion containing the USB, video, and Ethernet connections. Your motherboard ships with an I/O shield that fits into this rectangular cut-out. If you install that shield and then align your motherboard’s I/O panel, you should see the motherboard’s screw holes align with the stand-offs in your case.

If not, you may need to wiggle the motherboard slightly to make sure it snaps properly into the I/O shield and the stands-offs align. This may require some effort, but it shouldn’t require much force. If you’re forcing the motherboard, double-check how it’s aligned, as it may not be properly positioned. Be firm but gentle.

Don’t go wild while tightening screws, as you might damage the board if you put in too much effort.

Depending on the case and motherboard combination, pairing the two requires between six and 10 screws. You may find that not all holes match up with standoffs underneath. Drop a screw into a hole to see if it threads right away.

Like every set of screws, the first step is seating the screws and giving them a couple of precursory turns. Then, proceed in a star pattern, tightening each screw a little at a time. Don’t go wild while tightening as you might damage the board. You only need enough torque to hold the board in place without wiggling.

Once the motherboard seats comfortably in the case, there are a few necessary connections.

First, the motherboard’s power connection is a wide, two-row cable that fits snugly into a similar looking spot on the board itself. This 20-28 pin connector powers both the motherboard and the CPU. However, some boards have a second 4-pin or 8-pin connector for the processor, which resides near your CPU, typically in the top corner. If you have it, you’ll need to plug that in, too.

Second, connect the case plugs and buttons to the motherboard. A double-wide row of pins — the location of which will be noted in your manual — runs the USB ports, buttons for reset and power, and activity LEDs for power and storage.

These small cables run in a bundle from wherever the ports reside in the case. Proper installation can be difficult, however, due to their size. If you have a magnifying glass or a set of tweezers, now is a great time to use them. Some motherboards include an adapter that bridges these jumpers to the right connections on your motherboard. Otherwise, installing them is as simple as matching the labels on the pins with the labels on the connections.

The USB header connecting to your front-facing motherboard ports will be on its own. This connection is around eight by two pins, and they’re enclosed in a larger plastic housing. This header has a notch on one side that should clearly indicate which direction it plugs in.

Step 5: Install the CPU cooler and/or heat sink

With the motherboard now tethered to your case, you can wipe the sweat of concentration off your brow. Now it’s time for the CPU cooler or heat sink!

Installation is simpler when using the CPU’s packaged cooler. The process varies, however, given the different brands and generations. You’ll need to refer to the included instructions for specific details. The same is true for third-party coolers, which use a proprietary installation bracket. Following the included instructions is crucial to your PC-building success.

Every cooler needs thermal paste. It’s an excellent thermal conductor, allowing heat to transfer from the chip to the cooler with ease. Without it, your cooler won’t work very well, if at all. If you aren’t sure what type of thermal paste to use, it’s well worth doing some research, and we have a list of the best thermal pastes for you to choose from, too.

AMD and Intel apply it to their coolers in the factory, but third-party coolers require manual pasting. Unfortunately, rubbing goo on an expensive CPU isn’t as straightforward as it sounds.

When directed by the instructions, simply apply a single silver dot — about the size of a small pea — right in the center of the chip. After squishing the chip and cooler together, try not to wiggle or twist too much, to ensure a smooth, full connection. If you’re using your own thermal paste instead of what’s pre-applied, make sure to fully clean the cooler using coffee filters with a little bit of isopropyl alcohol, removing any trace of the previously applied paste.

For basic heat sinks, you’re now finished; just wait for the paste to cure. But the full fan system still needs power. Plug the wires from the fan into a four-pin connection on the motherboard, which should be close to the processor and labeled “CPU_FAN.”

Step 6: Install your graphics card

Not every system needs a dedicated graphics card (discrete GPU). If you want a stand-alone chip for graphics, like PC gaming, installation couldn’t be simpler. We’re also assuming for this step that the card you chose is appropriate for your case size, capabilities, and power supply.

Modern graphics cards use a PCI-Express (PCIe) x16 slot. It’s a long, thin connector located on the rear of the motherboard, below the processor. For the vast majority of motherboards, you’ll want to use the top PCIe x16 slot.

To seat the card in that slot, you’ll need to remove a rectangular backplate from your enclosure. It’s one of many thin metal brackets lined down the back of the case to keep it sealed up.

You’ll need to remove one or two, depending on the card’s width. Do this by removing the screw that secures the backplate to the chassis. Once removed, the plate should slide (or fall) out freely. Keep the screw as you’ll need it in a moment.

After removing the brackets, make sure the switch on the motherboard’s PCIe slot is pushed outward. Then, with the ports facing the empty spot where the backplate used to be, carefully line up the long series of contacts on the card with the appropriate slot on the motherboard. Once it’s lined up properly, a solid push on the top of the card should cause it to snap into place as the switch clicks back in to hold it.

You don’t need excessive force, but if you encounter a great deal of resistance, take another look at the backplate and PCIe slot to make sure both are clear and the motherboard is properly aligned. Also take note if there is a push-pin that locks the card in like your memory slots, as some motherboards use it as a safety measure.

Use the screws pulled from the metal brackets to fasten the back of the card into the same spot in the case. Again, they don’t need to be extremely tight — just enough to hold the card firmly in place.

The connector is designed to prevent improper installation, so if the connection isn’t easy, double-check your alignment to make sure it’s correct.

Most video cards need extra power apart from what the PCIe slot provides. If your card needs extra juice, you’ll see a PCIe power connector on the card’s side facing away from the motherboard or, in some cases, on the side facing the front of the case. This connector is a group of square plastic pins numbering six or eight.

The most powerful cards may have two such connectors. Find the appropriate connector on your power supply, typically labeled VGA, and slot it in. The connector’s design prevents improper installation, so if the connection isn’t easy, double-check your alignment to make sure it’s correct.

If you need additional help, we have a detailed guide on how to install a graphics card with additional information.

Step 7: Install any additional expansion cards

Graphics cards aren’t the only components that use PCIe slots. Other add-in cards include wireless networking, sound, video capture, and even storage. Their installation is no different than adding a discrete GPU.

First, remove the metal bracket in the back of the case that corresponds with the PCIe or other expansion slot playing host to your add-in card. Keep the bracket screw handy so you can use it to secure your new card.

PCIe slots have a small switch at the interior end, which you push down and outward to open the slot. After that, line up the row of contacts on the card with the slot and firmly push down. Once you properly seat the card, the switch flips up. Securing the card in place is as simple as screwing it into the back of the case and attaching any necessary PCIe ports.