Introduction: How to Build a Desktop Computer

Building a computer can be a very rewarding experience. Since you’re reading this, you’re probably thinking about building your next computer instead of buying one pre-built. This is a very viable option these days and can bring many benefits; you can learn a lot about computer hardware by building one, you get a totally personalized computer, you can choose better components and you may be able to save some money and have fun.
Additionally, if you are the sort of person who wants to understand how things work, if you take broken stuff apart just to see how it all fits together, if you have a drawer somewhere full of “parts” you think may come in handy someday, then you just may be in the right place.

Step 1: Understanding and Picking the Parts

The first step to building a computer is getting the right parts.Although there is an almost innumerable amount of parts to choose from, they all fall into basic categories. The essential components of every computer are the following:

Case/Chassis - This is the box that most people associate computers with. Although it holds every component inside, it is effectively useless on its own.

Power Supply – This powers the computer by taking power from your wall and regulating it to the motherboard, and on to the rest of your computer.
Motherboard – This is the centerpiece of your computer. Every other component connects to the motherboard.. Processor/CPU – The Central Processing Unit is the "brain" of the computer. It handles most of the actual computation.

RAM – Random Access Memory is the "short-term memory" of a computer. It is used by the CPU to store program instructions and data upon which it is currently operating. The more RAM, the more your computer can do at once.

Hard Drive – The hard drive is the "long-term memory" of the computer. Unlike RAM, the things stored on it remain even when the computer is powered down. All your programs and data are stored here, as well as your operating system.

Video Card/Graphics Card/GPU – While the CPU handles most computation, the Graphics Processing Unit (GPU) handles all computing related to visuals. These plug into a slot on the motherboard and provide a place to connect a monitor to your computer. If you are planning on using your computer for gaming or video watching/editing, a high-end GPU is recommended.

Now that you understand what each part does, it is time to pick them out. A great resource to use for your first build is Logical This spreadsheet-esque website will show you parts that will match your budget, allowing you to build anything from an extremely basic word processing device to a super powered behemoth of a machine.

Once you found your budget, head over to PC Part and plug in the parts you have chosen. PC Part Picker is a valuable resource that makes sure all of the parts are compatible and will also search the internet's top electronics stores to find you the best deals. The hardest part after ordering them is waiting for them to show up in the mail.

Step 2: Assembling Your Computer: Attaching the Motherboard

This step is the most fun, and most challenging part of building your computer. This is the part when you actually build it.

Before you begin, you should make sure to have a #2 Philips-head screwdriver, Needle-Nosed pliers, an Anti-Static Wrist strap, and a large, level work space. Ready? Let's begin.

Start by putting your case down on your work surface, with the case door facing up, and open the case.

Find the motherboard standoffs (spacers) that should have come with the case. They are screws, usually brass, with large hexagonal heads that are tapped so you can fasten screws into the top. These hold the motherboard up off the case preventing a short-circuit. Set these aside.

Now locate the screw holes on your motherboard and find the corresponding holes on the motherboard plate (or tray) in the case. Put a standoff in each of these holes on the tray and position the motherboard so that you can see the holes in the top of the standoffs through the screw holes in the motherboard.

Now fasten a screw through each of the motherboard screw holes into the standoffs underneath. These screws should be snug but not tight, there is no reason to torque down on them, hand tight is fine, otherwise you can damage the motherboard.
Once the motherboard is installed, it is time to plug the other components.

Step 3: Assembling Your Computer: Installing the CPU

Installing the CPU, and the CPU’s heat-sink and fan, are by far the most difficult steps you’ll have to complete during your build. Here, more than anywhere else, it will pay to read the instructions carefully, look at the parts, study the diagrams that came with your CPU and/or third party cooling solution, and make sure you thoroughly understand what you are going to do before you try to do it. During the process, if anything does not seem to fit or make sense, put the parts down and look things over carefully before you proceed. Some operations, especially installing the heat-sink/fan combination, can require pretty firm pressure, so don’t be afraid to push a little harder if you’re sure everything is set up correctly.

The details of the installation process differ in slight but important ways for each manufacturer’s processors, and even within a manufacturer's product line. Therefore, for these details, you should rely on the instructions that are provided with the CPU.

Step 4: Assembling Your Computer: RAM Memory Slots

Next, you will need to install your RAM (random access memory). Find the RAM slots on your motherboard; they will look something like the first picture above.. To install the RAM modules, first push on the levers (white plastic in the picture) on either side of the DIMM socket, so that they move to the sides. Do not force them, they should move fairly easily.

Put the RAM module in the socket. Line up the notch in the center of the module with the small bump in the center of the RAM socket, making sure to insert it the right way. Push down on the module until both levers move up into the notches on the sides of the module. There should be a small "snap" when the module is fully seated. Although this does require a fair bit of force, do not overdo it or you may break the RAM module. Although it may feel scary, this is one of the easiest steps in the process. You're doing great, let's finish this!

Step 5: Assembling Your Computer: Attaching the Power Supply

Installing your power supply is pretty straightforward. Generally there will be a bracket on the top of the case where the power supply is mounted and a few screws used to fix it in place. Some cases place the Power Supply differently, see the documentation that came with yours.

Once you get the power supply installed, make sure to check the motherboard documentation carefully for the location of the power sockets. You may then connect the main power, a 20 or 24-pin plug, into the motherboard. There may also be an additional four or eight-pin power lead that needs to be plugged in to the motherboard (the CPU power connector) usually located near the processor socket.

Step 6: Assembling Your Computer: Adding the Video Card/GPU

If your motherboard has a built-in video adapter you want to use, skip this section.

Consult with your GPU documentation to determine what type of card it is, and then install the video card into the appropriate socket. Check the motherboard for levers (or similar devices) that are part of the slot to help hold the card in place. These must be retracted before insertion of the card. Check the motherboard's manual for information on how to use these devices (if your motherboard has one.) Push the card into the socket (the slots are often pretty tight, do not be afraid to push it until it is well inserted), then screw it in at the top of the metal bracket. If it has a power connector, connect it to a 4-pin molex connector. When your card is properly installed, the line formed by the top of the card will be exactly parallel to the motherboard. If one side seems to be higher than the other, chances are that it is not fully inserted, press a little harder on the high side or pull it out and try again.

Step 7: Assembling Your Computer: Installing the Hard Drive

Next, install the hard drive. The method of installing your hard drive will depend on your case. Make sure to read the instructions on your case for more information.

Most hard drives are SATA (Serial ATA) which use simple, small cables for a data connection. The ends of the cables are L-shaped. Look carefully at the cable ends and the connector on the drive and match them up. Only one drive can be connected to each SATA port on the motherboard. Some SATA drives have two different power ports.

***Make sure you connect ONLY ONE of these ports to the power supply, connecting both can damage the drive.

Finally, plug a 4 pin molex power connector into your hard drive.

Step 8: Assembling Your Computer: Connecting Everything Else

In order to turn the computer on, you will need to connect the power button and while you are at it, you might as well do the reset buttons and front panel lights as well.

There will be a set of pins, usually near the front edge of the motherboard to which you will attach the cables sometimes already connected to the the front of the case, or if needed supplied with the motherboard. Most of the time the plugs will be labeled as the pins they will connect to in the motherboard, there they can be difficult to read since the print is very small or you may not be in the right orientation to do so. The documentation that came with your case and motherboard should tell where these connectors are.

In addition, you can connect any case-specific ports if they are supported by the motherboard. Many cases have front mounted USB, Firewire and/or sound ports.

Your case may have included several zip-ties. These are to make sure that all of your cables are neatly squared away. If a cable is loosely hanging within the case, it may damage the computer by snagging on a fan or interrupting a connection. If your case did not come with zip-ties, I recommend buying some.

Once everything is neatly tucked away, take a moment to check one more time that everything is as it should be. Double check, then triple check that you have made all the necessary connections and that you haven’t left any foreign objects (where’s that screwdriver?) in the case.

Close the case, connect your computer to an outlet (make sure to flip the switch on the power supply), say a short silent prayer, and press the power button.

Step 9: Installing the Operating System and Finishing Up

Now that you've physically built your computer, it's time to install the most important software that it will be running: the operating system (OS). Since this is a PC, most people (including myself) will run Windows. Other options are available, such as Linux, but that is far too advanced for a first-time build. Luckily, the installation of Windows is relatively easy. Simply follow the on-screen instructions, and your brand new computer will be up and running in no time!

Congratulations on accomplishing your first build. Since this is a brand-new computer, you will find that it does not come with any pre-installed software that may slow down your machine. I highly recommend Just check what programs you want installed, click the big green button, and Ninite will do the rest! It is completely safe and free.

You're done! That wasn't too hard, was it?