How to build a computer
Building a computer used to be a complicated process where careful selection of delicate parts was a necessity. When that collection of components finally booted for the first time, it was a triumphant experience. Knowing how to build a computer made you quite the tech-head.
Nowadays it’s easier than ever, with clear standards of compatibility, obvious choices for performance and value, and an actual building process that’s straightforward and well documented. That said, there are pitfalls to avoid and assumptions experienced builders make that newcomers won’t know.
To help out new PC builders and experienced enthusiasts alike, we’ve compiled this handy step-by-step guide that will take you from a pile of parts to a working computer in just a couple of hours.
This guide is all about putting your components together. If you haven’t selected and purchased all the hardware you need, stop reading and go check out our PC build guide, which outlines the recommended components for a variety of builds.
Have your parts? Good. Let’s get started.
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 of them in front of you, but 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.
You can feel it
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, it’s easy to all but eliminate with a few simple steps.
One easy 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, but turned off, achieves the same effect.
Apart from that, it helps to build in a room with a bare floor — carpets generate a lot of static — and wear rubber-soled shoes rather than socks. Many components are packaged in anti-static bags, and it’s a good idea to leave them there until just before installation.
Need help? Just ask
Building a PC for the first time can be a little tricky, but the good news is there are many resources to help. People who like building computers don’t often get the opportunity. If you have an enthusiast friend, they may jump at the chance to help put it together.
This guide is meant as a general overview of the process, and the instructions your parts came with may vary from our suggestions. When they do, default to the included instructions, and use our guide as a roadmap for the whole project.
Opening the case
Preparing the case is the easy part. The instructions should introduce you to the basic layout of your case, as well as offer up special instructions regarding component installation.
Lay the case in your work area and remove the side panel that provides access to the interior. For most cases, this means the left-side panel (as viewed from the front). Also remove anything that’s dangling inside the case, or if it’s attached, push it aside. Many cases have permanent internal wiring that can become a hassle later.
Before we start putting other parts together, we’re going to install the power supply, and then set the case aside for a few minutes.
The power supply
The first component to make its way into the case should be the power supply, or PSU as it’s more often called. Typically located at the rear of the case, usually in the bottom or top corner, the slot is easily located by searching for a square opening. This opening will have screw holes on at least two corners, and the PSU sits in it with a switch and female socket facing outward. Consult your case’s manual if you have trouble finding the proper location.
There are two main varieties of power supply: 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 supply, it’s best to leave the cables out for now and run them as you install each additional component. If all the cables are permanently attached, carefully bundle them up so they’re hanging out the open side panel of the case, for now. This will keep them out of the way while we install the rest of the components.
Installing the processor
We’re going to prepare the motherboard by installing the CPU, cooler, and RAM before fitting it in the case. It’s a lot easier to install them now, rather than after the motherboard is installed in the system.
In fact, depending on your case and cooler, it may not be possible to assemble your system with the motherboard in the case. 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.
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 that there are no sources of dust or liquid nearby.
Pick a side
Even though installing a CPU has become an easier task over the last few 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.
Modern Intel sockets have pins on the motherboard, instead of jutting from the processor, which makes installation easier. This part of the socket is called the contact array, and it’s very important not to bend or touch any of the pins on it — no touching! The square metal bracket that holds 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.
First, open the load plate. Do this by pushing down gently on the load arm and moving it out sideways from under the hook, and then lifting it up all the way. The lever action of the hook will open the plate, which you can easily flip up. If it’s a new motherboard, there may be a plastic or foam filler in the socket, which you can gently remove.
The CPU itself should have two small notches cut out of it, directly across from each other on the chip. With the contacts facing down, there should be only one direction where the notches will line up with the notches in the socket. Gently set the CPU in so that the outer rim lies flush with the socket body. This part doesn’t require any pressure.
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 will require 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.
With AMD CPUs, the pins are on the chip, with holes that they slip into on the socket itself. The load arm on the socket shifts the holes underneath slightly, gripping the pins on the processor when pressed all the way down.
If it isn’t already, lift the arm up so that it’s pointing straight up, and then rests a little further back. That will ensure the holes for the pins are wide open.
Instead of notches, we’ll be looking to line up the processor in the slot correctly using the golden triangle. The triangle should be engraved in gold on one corner of the CPU, and all you have to do is line that up with the triangle cut into the slot itself.
Once the processor is sitting 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 will require a fair amount of pressure to lock in place.
Remembering to install memory
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.
Direction is easy enough. Each memory stick has a notch in the contacts along the bottom edge that lines up with a block in the memory slots on the motherboard. 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, and one of which is how the RAM you bought is packaged. If it’s just a single stick of RAM, install it in the A1 slot and move on with your life (a diagram in the motherboard manual should label the slots, if it isn’t printed directly on the PCB).
There are more likely two identical sticks of RAM, 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. These sticks should be installed in channels on the motherboard 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 which 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. Easy!
The big moment — installing the motherboard
Installing the motherboard with all of the parts on it is easy enough, but it can’t just sit in your case. Most modern cases have spacers between the back wall and motherboard, known as standoffs, that are built in permanently. They act as a ground for the motherboard, while preventing the connections on the back from shorting.
Some cases will have removable stand-offs you have to install yourself. These are easy to identify because they look unusual — they’re essentially screws that have another screw hole on top instead of a head for a Philips or flat-head screwdriver. They’re usually copper or gold in color, which makes them easy to pick out.
The orientation of your motherboard is dependent 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 will be packaged 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 with it, you’ll find the screw holes in the motherboard align with the stand-offs in your case.
Well, generally. You may have to wiggle the motherboard slightly to make sure it snaps properly into the I/O shield and the stands-offs align. This may require a bit of effort, but it shouldn’t require much force. If you find yourself forcing the motherboard, double-check how you’ve aligned it, as it may not be positioned properly.
Depending on the combination of case and motherboard, attaching the two will require anywhere between six and 10 screws. You may find that not all of them match up with standoffs underneath, but dropping a screw in will reveal whether 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, tighten each screw a little bit at a time. Don’t go wild while tightening them, as you might damage the board if you put in too much effort; it just needs to be held in place without wiggling.
Once the motherboard is comfortably seated in the case, there are a few necessary connections. One is the power cable, which in the case of the motherboard, will be 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 is located near your CPU, typically in the top corner. If you have it, you’ll need to plug that in, too.
There are also case plugs and buttons that need to be connected to the motherboard to function properly. A double-wide row of pins, the location of which will be noted in your manual, runs the power and reset buttons, power and hard drive activity LEDs, and any USB 2.0 ports.
These small cables will run in a bundle from wherever the ports on the case are, and installing them is as simple as matching the labels on the pins with the labels on the connections. However, their size can make them very hard to properly install. If you have a magnifying glass, now is a great time to use it. A set of tweezers can come in handy, as well. Some motherboards include an adapter you can plug these jumpers into, and then fit to the right space on your motherboard.
The USB header that connects to your front-facing motherboard ports will be on its own. This connection is about eight by two pins, and they’re enclosed in a larger plastic housing. It has a notch on one side that should clearly indicate which direction it plugs in.
Now that’s done, and you’ve wiped the sweat of concentration from your brow, the next step is to install the cooler. Installation is simpler if you’re using the cooler that came with your processor, but it will vary greatly depending on the brand and generation, so use the included instructions for specific details.
That goes double for anyone using a third-party cooler, which will use a proprietary installation bracket. Following the included instructions is crucial to success.
Every cooler will need thermal paste. AMD and Intel apply it to their coolers in the factory, but users with a third-party cooler have to do it themselves, and rubbing goo on an expensive CPU isn’t as straightforward as it sounds.
Thermal paste is a necessary part of any cooler. This silver goo is 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. When the instructions indicate, simply apply a single 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.
Either way, the cooler is going to need 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.”
Get your game on with the GPU
Not every system needs a dedicated graphics card (GPU), but if yours does, no worries! The installation couldn’t be simpler. We’re also assuming for this step that the card you’ve chosen is appropriate for your case size, capabilities, and power supply. For a more detailed walk-through of GPU installation, make sure to check out our video guide.
Modern graphics cards take up a PCIExpress (PCIe) slot. It’s a long, thin connector located on the rear of the motherboard, below the processor. To seat the card in that slot, you’ll need to remove a backplate from your enclosure. It’s one of a row of thin metal brackets on the back of the case to keep it sealed up.
You’ll need to remove one or two, depending on the width of your card. Do this by removing the screw that secures the backplate you want to take out. Once removed, the plate should slide out freely. Keep the screw as you’ll need it in a moment.
Once the brackets are clear, it’s time to seat the card in the PCIe slot. First, make sure the switch on the slot on the motherboard 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.
Not much force is required, so 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 feature that safety measure.
Use the screws you 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 as tight as possible — just enough to make sure the card is held firm.
Most video cards need extra power apart from what the PCIe slot can provide. Those cards that do will have a PCIe power connector on the side of the card facing away from the motherboard or, in some cases, on the side facing the front of the case. The 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 is designed to prevent improper installation, so if the connection isn’t easy, double-check your alignment to make sure it’s correct.
Additional expansion cards
Graphics cards aren’t the only component that uses the PCIe slot, and the list includes wireless networking cards, sound cards, and even hard drives. The process for installing them is very similar to the GPU process.
First, remove the metal bracket in the back of the case that corresponds with the PCIe or other expansion slot you’ll be installing the device into. Keep the screw from the bracket handy, as we’ll use it to reattach the new card.
PCIe slots have a small switch at the interior end, which you can push down and outward to open the slot. Then line up the row of contacts on the card with the slot, and push down firmly. Once the card is seated the switch will flip back up. Securing the card in place is as simple as screwing it into the back of the case and attaching any necessary PCIe ports.
There are a few different types of PCIe slots. A good deal of expansion cards use the “PCIe 4x” slot, which is much shorter than the full PCIe slot used by video cards. A quick check of your motherboard’s connectivity, and the size of the connector on your card, will make it obvious which slot is appropriate. If in doubt, refer to the expansion card’s manual.
Installing a drive of every type
There are three different storage drive sizes you’re likely to encounter, and they all mount and connect differently. Generally, spinning disk hard drives (HDD) are the larger 3.5-inch size, while newer solid state drives (SSD) have adopted the smaller 2.5-inch size. There’s also the even smaller M.2 format and PCIexpress drive format, which tend to be thin sticks with bare chips measuring around 1 x 3 inches.
We’ll start with 3.5-inch data drives, which are usually mounted up high at the front of the system. Your case is almost guaranteed to have at least one slot dedicated to this type of drive. Installation will depend on the enclosure. Most have a simple hard drive cage. Installing a drive means slotting it into a mount on the cage and aligning the screw holes on the sides of the drive with those on the side of the cage. Make sure that the power and data connectors on the drive face inwards, toward the motherboard. Once aligned, screw the drive into place.
Expensive cases may have a “tool-less” installation system. As the term implies, this design should mean it’s possible to install the drive without a screwdriver. Usually this means placing the drive into a cradle or cage that then slots into the case. Refer to your enclosure’s instructions for specifics, since the technique varies from one brand to the next.
When it comes to 2.5-inch drives, the mounting process and location is going to vary a bit more. Some cases have a cage, similar to the 3.5-inch mounting, where the SSD can just slide in — no rivets, no screws, no brackets. If it doesn’t, the SSD will need an adapter to fit it in a 3.5-inch bay, which is accomplished in one of two ways. Either the larger bracket has screw holes inside which allow you to screw the drive into the middle, or the case will include a bracket that adds some extra girth to the 2.5-inch drive.
Hard drives require two connections as well, one for power and one for data. The good news is that both are L-shaped, so it’s hard to plug them in the wrong slot or the wrong direction.
For those with a newer M.2 drive, you’ll want to look for a slot the size of the small end of the drive, and a screw a few inches away. Remove the screw, insert the contact end into the slot, then push down gently until you can use the screw to hold the drive in place once again.
PCIexpress storage drives can be mounted in much the same way graphics card are in an available PCIexpress slot.
While optical disk drives are on their way out in the computing world, there are still a lot of builders who prefer to include them. The optical drive mounts in a 5.25-inch slot that looks similar to the 3.5-inch slot where we installed the mechanical drive, and the installation procedure is similar as well.
The drive itself loads into the system from the front, but if it doesn’t fit, you may need to remove the front faceplate of your system. If that’s the case, check your case’s manual for specific instructions.
Once all obstructions are clear, slide the drive in from the front of the case until it’s flush with the faceplate, or the other front-facing drives. Then, simply attach the included screws through the side of the case to mount it there. The cables should be similar, if not identical, to the ones used for the 3.5-inch hard drive. There’s no real way to install the wrong ones, or install them in the wrong direction.
Preparing to boot
Now before you get too excited and hit that power button, it’s worth running back through the system to make sure everything is properly seated and connected. Let’s start with the components found in every machine.
The motherboard is usually easy to spot if it isn’t plugged in. Most PSUs have one wide cable that’s obviously intended for this slot, with no other connections on it. It should plug into your board somewhere near the PCIe slots, but location will vary.
Your motherboard is also likely to have a second, four-pin or possibly eight-pin, connector. This powers the processor. You may have to look through your power supply’s available connectors with a keen eye to find this, because it looks a lot like a PCIe power connector. But don’t worry — a PCIe connector won’t fit, so improper installation isn’t possible.
The CPU cooler also needs power, but it gains it from the motherboard. Its power cable shouldn’t have to go far though, as most motherboards keep the plug close by the socket. The little wire is just three or four sockets, and connects to a set of four pins on the motherboard.
The hard drives need their own power sources too, in the form of L-shaped SATA connectors (unless it’s a PCIe drive). Typically, a string of three or four runs straight off the power supply, with just that type of connection on it. These can’t be installed the wrong way, either.
Finally, high-powered graphics cards need their own power connection, usually in the form of a black rectangular connector with six or eight pins. These plugs are brightly colored and easy to spot, and only fit in the interior end of the card in one orientation. If they aren’t plugged in, the fans on the card won’t spin, and it won’t produce any video output.
The final steps
Now that you’ve double-checked everything, turn on the power supply, and press the power button on the front. A lot of systems don’t boot correctly the first time, so don’t get discouraged if you need to go back and check connections again.
Once it does boot, you’ll need to install an operating system (OS). Luckily, we’ve built a handy guide that walks you through that process clearly, and succinctly. If you don’t have another PC around to download the ISO, you can purchase a USB thumb drive from Microsoft with the OS image ready to go.
Once that’s taken care of, you may need to install some drivers. Modern chipsets are already supported in Windows 10, and the OS will automatically download and install the rest of your drivers in most cases. Check the “Update & Security” menu in the Settings pane for more information regarding this process.
If that doesn’t work, the chipset driver for your motherboard will handle most connectivity and onboard features, and usually only discrete graphics cards will require a driver of their own, although this varies greatly based on motherboard and component manufacturer. Check out the AMD page for Radeon drivers, or the Nvidia page for GeForce drivers, and remember to check component boxes for install discs and other information.
With some luck, and a lot of attention to detail, your system should be fully operational. Make sure to keep an eye out for any error messages, and hold your hand outside the case fans to make sure air is flowing and isn’t too hot, at least for a few weeks. If something breaks, or needs an upgrade, you’re fully equipped to deal with it. Just watch out for static.