Introduction: How to Assemble a Basic Desktop PC

Picture of How to Assemble a Basic Desktop PC

This set of instructions will help you assemble a basic computer capable of running most modern software packages encountered by a casual user. Modern computers become more affordable when users supplement their monetary investment with a few hours of effort. This computer build will be very basic and will be the minimum hardware necessary to have a functional system. After you have all of the parts and materials needed, it will take between 2 and 4 hours to assemble your computer and you will need to be able to use simple hand tools, such as a screwdriver and a pair of pliers.

Step 1: Procuring Parts

Picture of Procuring Parts

First you will need to buy the parts necessary to build the computer. The parts we will use in this project are labeled in figure 1:

1. Processor (CPU)
2. Computer Case
3. Optical Drive (DVD RW and SATA capable)
4. Memory (RAM)
5. Power Supply
6. SATA Cables
7. Motherboard (SATA Capable)
8. Processor Fan
9. Case Fan
10. Hard Drive (SATA Capable)
11. Assortment of case and drive screws (Not Pictured)
12. Flowers (necessary if you are invading the space of your significant other)

Most, if not all of these parts can be bought together in what is known as a “barebones kit”. In this instance, the case, motherboard, cpu, hard drive, and memory were bought together from as a barebones kit for around $200. The DVD drive and cables were purchased from for less than $30 before shipping. There is an obvious financial advantage to buying parts bundled together, but less obvious is the benefit you will realize from the amount of time you save trying to research parts compatibility.

Caution: Double check the manufacturer’s specifications on all items before you purchase them. Kits are supposed to contain compatible parts, but mistakes can happen.

Step 2: Gather Tools and Supplies

Picture of Gather Tools and Supplies

Gather the tools you will need for the project:

  • Screwdriver (for slotted and Phillips head screws)
  • Wire cutters and strippers
  • Needle-nosed pliers
  • Utility knife
  • Small flashlight
  • Adjustable wrench
  • Small container to hold screws
  • Heat sink compound
  • Grounding Strap

You may not use every single one of these tools in every installation, but it is best to have all of them on hand in case you have a use for them.

Warning: Using incorrect tools for a task (such as turning a screw with a knife blade) can cause equipment damage and bodily injury.

Step 3: Open the Case

Picture of Open the Case

Open the computer case by removing the side panels. Find the screws that hold the side panels in place and remove them (shown in figure 3 circled in red). The panel is removed by first sliding it back (figure 4) then lifting it away from the case (figure 5).

Warning: Case may have sharp edges. Handle with care to avoid injury.

Step 4: Prepare the Case for Assembly

Picture of Prepare the Case for Assembly
Three things need to be done before assembly begins:
  • Remove any parts or packaging materials that may have been shipped inside the case (figure 6).
  • Remove the cover for the optical drive. On our case, we will be removing the cover on the highest drive bay to mount our DVD drive as shown in figure 7. Do this by pressing in the retaining tabs shown in figure 8.
  • Make note of the cables pre-installed in the case. These should be front panel connections for features such as the power switch, audio jacks and usb ports. If they are not labeled, consult the manufacturer’s documentation and label them yourself now before other parts are installed in the case (figure 8).

Step 5: Ground Yourself

Picture of Ground Yourself

Put the grounding strap on your wrist (Figure 10) and connect the other end to the computer case. If your strap is not equipped with a clip to hook to the case, find a place to wedge against the metal as shown in figure 11. This will prevent any buildup of static electricity on your body from damaging the computer components.

Caution:Static electricity can ruin computer components. Always wear a grounding strap when handling any internal components.

Step 6: Install Motherboard

Picture of Install Motherboard
To install the motherboard we need parts that should have been included with your purchased components:
  • I/O Bezel is a trim panel installed in the back of the case that surrounds the interface ports on the motherboard. It should be included with the motherboard. Figure 12 shows the contents of the motherboard box.
  • Standoffs are installed in the case screw holes to create a riser that separates the case and motherboard. The screws install into the standoffs as shown in figure 13. Screws and standoffs should be included with the case, but it is a good idea to order these items just in case they aren't included.
Follow these steps to install the motherboard in the case:
  1. Install the I/O bezel plate into the opening in the back of the case (figure 14). It pushes in from the inside.
  2. Install standoffs in the case. The standoffs screw into the motherboard mounting holes shown in figure 14. Check the screw hole locations on the motherboard for exact placement.
  3. Lower the motherboard into the case and align with the I/O bezel.
  4. Install the screws.
Figure 15 shows the motherboard installed in the case. It works best to leave the screws loose until all of them have been started and the board is aligned with the bezel.

Caution: To prevent damage to the motherboard it must only contact the standoffs and screws. All of the standoffs and screws must be installed.

Step 7: Install Hard Drive

Picture of Install Hard Drive
The hard drive is the device that stores all of your data. It is 3.5" wide and needs to be mounted so that you can gain access to the cable connections on the back (figure 16). If that is not possible you may need to connect cables before you install the drive. To mount the drive:
  1. Find a 3.5" drive bay to install the drive in. If you have trouble finding a place to mount the drive consult your case documentation for suggestions.
  2. Slide the drive into place until the screw holes on the sides are lined up with the holes in the case.
  3. Install the screws.

Step 8: Install Optical Drive

Picture of Install Optical Drive
The optical drive is 5.25" wide and is installed in the drive bay that we removed the cover from in a previous step. Cable access considerations apply to this drive also. To install the drive:
  1. Slide the drive into the drive bay until the screw holes are lined up and the front of the drive is flush with the front of the case (figure 18). Make sure that it is orientated correctly.
  2. Install the screws.

Step 9: Install the CPU

Picture of Install the CPU
The CPU is the brain of the computer. It is installed on the motherboard in the socket shown in figure 20.To install the CPU:
  1. Find the corner marking that designates pin 1 of the CPU as shown in figure 19. On this AMD brand processor, the corner is marked with an arrow. Consult the manufacturer's documentation for specific information about your processor.
  2. Lift the small metal rod next to the socket as shown in figure 20.
  3. Find the corresponding marking on the CPU socket and insert the CPU so that the markings are lined up.
  4. Push the rod down to lock the processor in place (figure 21).

Step 10: Install RAM

Picture of Install RAM
The RAM is the temporary memory location that the processor works from. Permanently stored data is pulled from disks and stored in RAM while the processor works with it. The memory is easy to install:
  1. Set the RAM board in the socket as shown in figure 22. Check to see that the notch in the board is in the correct location. If it is not, turn it around 180º.
  2. Press firmly on both ends of the board to set it into the socket. Make sure the tabs lock into place as shown in figure 23.
Caution: Pressing the boards in when the tab is not aligned could cause damage to the RAM boards as well as the motherboard.

Step 11: Install the CPU Fan

Picture of Install the CPU Fan
The CPU fan is really a combination of a heat sink and fan together. The unit draws heat away from the CPU . To install the fan:
  1. Place thermal compound to the CPU following the instructions provided with the compound.
  2. Set the fan assembly on the CPU with mounting tabs aligned.
  3. Pull the locking rod down on the fan assembly to lock into place.
  4. Connect the fan assembly's power connector to the motherboard. Consult the manual to determine proper placement.
Caution: Failure to apply thermal compound will result in insufficient cooling and will cause damage to the CPU and/or motherboard.

Step 12: Install Case Fan

Picture of Install Case Fan
The case fan is usually installed on the back panel of the case. If the fan mount is not obvious consult the case documentation. To mount the fan:
  1. Align the mounting holes by holding the fan to the mounting pad on the inside of the case as shown in figure 25. The fan needs to be mounted so that it blows air out of the case.
  2. Insert the screws from the outside of the case and tighten.

Step 13: Install Power Supply

Picture of Install Power Supply
Consult your case documentation for details and then follow these directions to install the power supply:
  1. Align the mounting holes in the case and power supply as shown in figure 26.
  2. Insert screws and tighten.

Step 14: Connect Cables

Picture of Connect Cables
With all of the components installed in the case, the jungle of wires can be daunting. It is important to consult the motherboard manual in order to make sure proper connections are made. There are two kinds of connections, power and data.
  • Every device that has been installed needs power. In figure 27, the power supply connectors are shown. The motherboard has two power connections, and there are two connectors specifically for SATA devices (drives). The other connectors will run fans and other non-SATA devices.
  • Data cables connect drives and front panel devices to the motherboard. Please consult the motherboard documentation for the exact placement of connectors.
Warning: Incorrect connections can damage components and cause bodily injury.

Step 15: Wrap-up

Picture of Wrap-up

Now that the components are completely installed, the last thing to do is to reinstall the side panels on the case. The computer is now ready to be turned on and to have software loaded on it. If the computer has problems starting up, check all component connections and mounting to make sure that you have hooked everything up correctly. Consult individual component manuals for specific troubleshooting information if problems persist.


RovelN (author)2017-12-14

this procedure is good for new people ho want to make their own system unit, thank to.

AadilS6 (author)2017-12-14

i need multiple screen what do i need to do that

Y UD (author)2017-12-07

thnx for helping me with my assignment

Craftboy805 (author)2017-05-08

Nice tutorial you have here, I used this for referance multiple times.

Spannerz (author)2011-02-10

Agreed (I clean mine with a simple paintbrush)
BTW it's facing the wrong way. the label is supposed to face outwards, which is also the way the air should flow. you wanna suck the hot air out rather than sucking more air in. It also makes less noise ;D

Craftboy805 (author)Spannerz2017-05-08

No, I'm pretty sure the fan is mounted so it will suck air out...

gladwynt (author)2017-03-31

it is a good tutorial

IRAGENAF (author)2017-02-23


H M SriguruP (author)2017-02-02


suhail m subair (author)2017-01-16


can i use two rams in a computer at a time with different sizes

DevenJ4 (author)suhail m subair2017-01-22

Yes but if those two RAM capacity has to be similar..

memetrahs (author)2017-01-09

thes es a god tutorrial

Mary JoyT2 (author)2016-10-12

Hi thanks to this post... I want to try this out... but please indicate the brand you used in every computer order to detect what are the parts that fit together.

how to obtain that "ground stuff"?

KellenL2 (author)Mary JoyT22016-10-21

Use to find compatible parts.

king Wellah_Wolf (author)2016-06-26

you just made me pass my Assignment in computer systems electronics

RohanD16 (author)2016-02-03

I Did It With Intel Core i7... Thanks

SandeepA8 (author)2015-12-22


malleswararaog (author)2015-12-17


PardeepM (author)2015-08-02

can i chnge ram replace 1.5 GB to 2 or 4 GB RAM simply by exchange ram ?

dstclair22 (author)PardeepM2015-09-24

how can you tell me ten steps

JacobL10 (author)2015-07-20


aprajapati2 (author)2011-11-15

but how can i install OS ?

ReeceS3 (author)aprajapati22015-04-11

I know this is late (3 years late infact) but if it still helps you you can use a disc if you buy a os from somewhere that sells them, and then insert it into your computer and it will ask you to choose options that you want to set for the os.

Muralita (author)2014-11-11

while it is nice to assemble the hardware, a computer isnt a computer unless it works! That means installation and testing of software is a key part of the build. Hope future builds will incorporate this.

AbdulR1 (author)2014-08-20

Preparing a computer can be a productive experience in the life.

Gramjen (author)2011-02-21

Thanks for the detailed information on computer parts and accessories needed to build a computer from scratch. This is really good information and the format of the post is really well done.

Spannerz (author)2011-02-10

I'd just like to make a point here - the audio cables have both 'HD AUDIO' and 'acc '97" plugs. the motherboard I'm using is *supposed* to support HD audio however it absolutely refuses to run with HD plugged in - only '97 did. T be honest, if the plugs just lead to a Mic and Headphones port (2 channell) '97 is sufficient.

Spannerz (author)2011-02-10

Dude, what case did you use? or who made it? I bought one oh so very similar, only less bays (the top one has DVD logo stamped on it and a flap opens to revel DVD tray - emac style) the front is red and the power button glows blue.

JustinjjhcSchubert (author)2010-09-02

I have found that an AMD CPU can sometimes run Hotter then Specified which will Cause Freezing and Crashing. so getting a Copper Overclocking Heat sync is always a good Idea and conductive past Also most Forms of Microsoft Systems If you are not Using RedHat which is free Require 2GB Ram or Better. so get the 500 DDR 4GB ram or Better granted they are almost $200.00 but good Ram is Worth it... Also it is a Good Idea to Buy heat syncs for your MB bridge chips

Miles Tails Prower (author)2010-08-02

Man, that fan is DUSTY! Clean it before you install it, man.

ben_k (author)2010-06-26

You did not install RAM or a CPU cooler, and your case fan probably should be an exhaust, not an intake given its position.

jimirayblues (author)ben_k2010-06-26

See Step 10: Install RAM. From Step 12: "Align the mounting holes by holding the fan to the mounting pad on the inside of the case as shown in figure 25. The fan needs to be mounted so that it blows air out of the case". The CPU fan is mentioned briefly when the CPU is installed. Do you think this should be a separate step to make it more clear?

ben_k (author)jimirayblues2010-06-26

It's just that you did not show the ram or cpu cooler in your final pictures, and the fan in the picture does not blow air out of the case. Adding a step for the cpu cooler would probably be a good idea.

About This Instructable




More by jimirayblues:How To Assemble A Basic Desktop PC
Add instructable to: