How to Build a Computer From Different Parts

The inside of a computer

Building your own PC is fun and easy, and can be done with a few hundred dollars in components and some simple hand tools. Besides being an interesting hobby and a good way to learn about computer operation, building a PC from parts can save you some money over purchasing a complete PC. The knowledge gained is also useful for troubleshooting and repairing computers.

Things You'll Need

• Computer case with power supply
• Computer monitor
• Motherboard
• Memory sticks
• CPU
• CPU heatsink/fan
• Hard disk drive
• CD-ROM drive
• Video card
• Ethernet card (optional)
• Screwdriver
• Needlenose pliers
• Power cable
• Keyboard
• Plastic zip ties

Instructions

Building a Computer

1. Unpack the case from its box and protective packaging. Verify that all parts indicated on the manifest are included. The case should be of the same form factor (e.g. ATX) as your motherboard. Check the back of the case to see if the connector holes match up with those on your motherboard. If not, install the plate with connector openings that came with your motherboard. Generally this snaps into place.

2. 

   CPU, pin side up, fan attached

   Insert the CPU into the CPU socket on the motherboard. Be sure to discharge any static electricity from your body by touching a bare grounded metal surface such as a faucet before handling the motherboard, the CPU or other electronic components. Be careful not to bend any of the many pins on the bottom of the CPU. The CPU will only fit into the socket in one orientation, and no force should be necessary. If it won't go in easily, make sure the orientation is correct. The socket will have an arm or other device for securing the processor into the socket. Check the instructions that came with your CPU to determine the method for your processor.

3. 

   CPU with heatsink permanently attached

   Attach the CPU heatsink/fan to the CPU. Most attach with small clips onto prongs on either side of the CPU socket; needlenose pliers may be helpful. Your CPU or heatsink instructions will explain the particular method used for attaching the heatsink. Avoid touching the surface of the heatsink, as the natural oils in human skin can degrade its thermal transfer properties. The fan lead connects to pins labeled "FAN" on the motherboard; consult your manual for its exact location on your model.

4. 

   A typical computer motherboard

   Screw the motherboard to the case using the provided screws and mounts. Depending on the case model, it may be necessary to partially disassemble the case to get access to the motherboard mounting area. The mounting holes in the motherboard should line up with corresponding holes in the case, and the connectors for the keyboard, USB ports, etc. should line up with the holes on the back of the case. Tighten the screws firmly but not too firmly; be careful to avoid cracking the motherboard with too much tightening.

5. 

   Motherboard's ATX power socket, in white

   Connect the power supply to the motherboard's power connector. The power supply has many drive power connectors and one motherboard connector with a different appearance. Consult your motherboard manual for the location of the power connector on your particular board. The connector will only fit into the motherboard with the correct orientation. No force should be necessary. If it won't go in, try reversing the plug.

6. Connect the case indicator LEDs and speaker to the motherboard. The case LEDs show whether the power is on and when the disk is active. The location of the LED pins varies according to the board model; the manual will show their exact location, and they're typically marked "PWR," "SPKR," and "DISK." The connector wires are typically much longer than necessary. They can be tied back with a plastic zip tie for a neat appearance.

7. Mount the hard drive and CD-ROM drive into the case's drive bays with the provided screws. Make sure that they're in "cable select" mode before mounting them. Most drives come preset at the factory to "cable select" mode, but it's a good idea to double check so they don't have to be unmounted to change them later.

8. 

   Hard drive power connection

   Connect the power supply to the drives. Note that the power supply connectors are designed to fit in the sockets only in the correct orientation. Do not force it. Try reversing the connector if it won't go in easily.

9. 

   IDE cable showing orientation prong and blocked pin

   Connect the cables, typically provided with the motherboard, to the motherboard's sockets and to the hard drive and CD-ROM drive. Most connectors are notched on one edge to fit a corresponding prong on the cable, to prevent cable reversal. Some also have a blocked pinhole. As always, do not force the connector if it doesn't seem to fit; try reversing it.

10. 

    A video card

    Insert the video card and network card into the appropriate slots on the motherboard. The motherboard manual will identify the different kinds of slots. Most cases have some sort of covers on the openings at back of the case that must be removed in order to insert a card into a corresponding slot. Remove the appropriate cover either by unscrewing it or by twisting it with pliers and snapping it out.

11. 

    Common DIMM memory sticks. Note the orientation notch in the bottom edge.

    Insert the memory (RAM) sticks into their slots on the motherboard. Consult the manual for the locations and order of use. Hold the sticks only by the edges. They are designed to fit into the slots only in the correct orientation and with very little force. If they won't slide easily into the slot, try reversing them. Never force the memory into the slot.

12. Plug the computer in and power it on. Be careful not to touch anything inside the computer when power is applied. Check to see that the fans all operate properly and the hard drive spins. If something doesn't work, disconnect the power and check the connections. When the computer starts up, you should hear a single short beep from the speaker. If instead you hear more than one beep (or from some units more than two) or a long, continuous beep, this means that something is connected improperly. Disconnect the power and make sure that the memory sticks and all cards and connectors are firmly and fully seated properly in their sockets. If the problem persists, start taking things out one by one to isolate the issue via the process of elimination. Connect the monitor to see how far into the boot process the machine is getting and for any messages the BIOS may provide.

13. Connect the monitor (if you haven't yet), keyboard, mouse, Internet or network cable and external speakers if desired and restart the computer. Enter the BIOS setup screen at boot. Set the time and date and autodetect the hard drive parameters. Make sure that "boot from CD" is enabled. The exact procedure for doing this varies considerably by motherboard model; check the manual for yours for details.

14. Insert the boot CD for your operating system and follow the on-screen directions and your operating system manual to install the operating system onto the hard drive.

Tips & Warnings

• There is a wide variety of computer parts available, and many combinations will not work. The motherboard form factor must match that of the case. The CPU socket on the motherboard must be the correct one for your CPU -- and there are many types of socket. The memory must be the correct type for your motherboard. The video card slot on the motherboard must match the type of connectors on your video card. If the video card is a high-performance model it may be very large. Make sure the case allows enough room for it. The motherboard and power supply connectors for your drives must match the type of connectors on the drives, typically SATA or IDE. Ask the sales representative who sells you the parts to ensure that the parts you buy will all work together. If this is your first time building a computer, buy parts in retail packaging so they come with any brand-specific instructions. Parts marked OEM generally will not include such instructions.

• Computer cases often have sharp metal edges exposed inside. Be careful to avoid cutting yourself.

• Computer components are very delicate and easily breakable. All parts should slide into place easily with minimal pressure. Never force anything.

• Electronic components are highly sensitive to static electricity. Discharge any static charge on your body by touching a bare grounded metal surface such as a faucet prior to handling electronics.

• Disconnect the computer from the electrical wall socket before working inside, to minimize the chance of shock or damage to parts from a dropped screw or other part.

References

• Build Your Own PC
• My Super PC: How to Build a PC
• Tech Report: How to Build a PC