Daniel D'Agostino's Information Technology website

PC Building Tutorial

By Daniel D'Agostino, 7th May 2008


In April 2008 I realised I needed a Linux-dedicated machine, so I decided to build a new PC. This was the second PC I built, and the idea was to buy the bare minimum necessary to build a PC, albeit the parts had to be decent. This time, I decided to document the process by taking photos, and the result is this tutorial on how to build a simple PC.

This tutorial doesn't assume that you have any hardware knowledge at all. I knew nothing about hardware when I built my first PC; in fact I built that first PC to learn how it's done. Assembling a PC is like a jigsaw puzzle: the pieces fit in particular places and it's difficult to go wrong. You just have to be careful about a few things, which I will mention later.

In this tutorial I only explain how to build a basic PC. It is up to you to look around the local computer shops and find the best deals on PC parts.

What you will need

As a bare minimum, you will need the following parts:

  1. A CPU (and a CPU fan) - this is the brain of the computer... everything passes through it.
  2. A motherboard - this is the circuit board which connects all the computer's components.
  3. A hard disk - everything permanent goes here, including your operating system.
  4. RAM - this is like the workspace of the CPU; things that are being processed go here.
  5. An optical drive - if you want to install an operating system, you will most likely need to boot it and install it from a CD or DVD the first time.
  6. A tower - this is the case or the box that all the parts above are attached to.

Here we are assuming that a power supply comes with the tower, and that the motherboard has onboard video. If either of these are missing, you will have to buy them over and above. A 400W power supply should be fine for the average PC. As for video, you should buy a video card only if you intend to make heavy use of graphics (e.g. gaming); otherwise go for a motherboard with onboard video.

Onboard video means that there is a kind of video card built into the motherboard, so you can connect your monitor to the VGA connector (blue) on your motherboard instead of using a video card. Of course a video card is always more powerful, but onboard video is still perfect for anything that isn't graphics-intensive. The only real downside to it is that onboard video will take up a portion of your RAM (usually around 256MB) to use as video memory. Graphics cards have this memory built into the card... today's cards even have their own 'CPU', called a GPU, but that's another story...

Step 1: Get the parts

Above are the parts I bought for my PC. You can see the motherboard (the ASRock box), the DVD drive, the network card, the power supply, a couple of SATA cables (more about these later), the hard disk, a CPU fan, the CPU itself, and some RAM. In case you're wondering, the thing at the bottom-left is actually the receipt. In the second photo you can see the box containing the tower.

You'll notice that there are a few things I bought that aren't in the list of very basics. One of them is a network card. Like video and sound, this should be built into your motherboard. The reason I decided to use a network card was that my motherboard didn't have Gigabit LAN, which means that networking works a bit slower. This isn't so much of a problem, but since I had a network card that I wasn't using, then why not use it...

As for the cables... you will need a couple of power cables. You will definitely need one for the tower and one for the monitor. Some power supplies have an extra power slot that gives power to the monitor, so you can optionally use that instead of taking up another wall outlet.

Above are the DVD drive, network card and hard disk (with cables) respectively. DVD drives and hard disks can be connected to the motherboard using two different types of cables: IDE or SATA. In this case, mine are both SATA. I won't go into the differences between IDE and SATA, but SATA is said to be faster. What concerns us here is that SATA (unlike IDE) uses two separate cables for data and power. The data cable is the red one, while the power cable is the one next to it (which is actually a converter that connects to the power supply).

Network cards, sound cards and the like fit into expansion slots in the motherboard called PCI slots. Video cards, on the other hand, are more demanding and use a particular slot called PCI Express.

Above are the remaining parts. The left photo shows the CPU fan (the big akasa box), the CPU (the small thing below it) and the RAM (on the right). The CPU fan is actually made up of two parts: the heatsink and fan. This is basically a whole cooling system because a CPU gets very hot. Without cooling, the CPU may very well blow up (see video on Youtube: "What happens when a fan stops working").

The middle photo is the motherboard's box, and the right photo is the tower, still in its box.

Step 2: Open the tower

The above photos show the back and front of the tower. The front should be familiar to everyone... There are the usual power and reset buttons, a card reader, a couple of USB slots, and the audio jacks for headphones and microphone.

The back of the tower is even more important. The top part (which is on the right of the photo) is the power supply - there is a socket for the power supply (and consequently, the whole PC) to take power, another one below it which is optional for a monitor to take power from, and the vent from where the PSU's fan throws out hot air.

In the middle part of the back of the tower there is a space where the motherboard's connectors will fit. This may be a blank space, or there may be a metal bracket, as in this case, which you will have to remove. Beside the connector area is an air outlet; there is usually a fan on the inside. At the bottom (left in the photo) of the back, there is an area with metal brackets which can be removed to expose any expansion cards (including sound, network and video cards).

Grab a screwdriver and remove the screws that lock the tower's side panel to the back of the tower. In this photo, they are the two screws at the bottom of the photo. Then you can slide out the side panel as shown above. You will work more comfortably if you remove both side panels.

With the side panels removed, take a look and see what's inside the tower. The metal skeleton inside it is called the chassis (pronounced shazzy), much like the skeleton of a car is also called the chassis.

The rest of the contents of the tower will vary from tower to tower. You should always get a small plastic bag containing several screws, which you will use to fasten the motherboard and the drives to the chassis. Since my tower came with a power supply, you can see the power supply at the top of the tower. The power supply will always have a big bundle of wires (see top middle photo above) - these are used to give power to the various parts of the PC. I was also lucky enough to get a power cable with the tower (top left photo above), which means I bought one for nothing.

Another set of connectors you'll notice is that coming from the front panel. There are three photos above showing these little connectors. These are the connectors that connect the power button, reset button, hard disk light and any other front panel ports (e.g. USB ports and audio jack) you may have, to the motherboard.

The bottom-right photo above shows the screws (on the left), the PC speaker (on the right), and a piece of paper showing where each screw goes... you will only get this with your tower if you're lucky. Those two little white things on the right don't come with every tower either... they fit into the side of the chassis to provide an extra two holes into which to screw the motherboard.

Step 3: Fit the motherboard port frame into the tower

Open the box containing the motherboard and see what's inside. The left photo above shows the contents of the box... a bunch of cables, a metal frame, the manual, and the motherboard underneath a cardboard divider. The middle photo is a first glimpse at the motherboard. At the bottom you can see the various ports, which will come out of the back of the tower. The metal frame fits onto those ports.

The white grid and black enclosure towards the left part of the motherboard is where the CPU and its heatsink/fan will go. The white grid is, in fact, the CPU socket. There are different sockets for different CPUs; this one is AM2, which can take most of the latest AMD processors. The black enclosure is the heatsink retention module.

The long yellow things at the top are where the RAM fits in. The blue thing on top of it (and, I suppose, also the black thing on the right) is where the IDE cable fits in... but since all my drives are SATA, I won't be using it. The SATA cables go into the red things at the top-right part of the motherboard. The orange 'ASRock' box at the centre, if I remember correctly, is where the onboard video is located. The PCI and PCI-Express slots are the white things on the right.

The photo on the right shows the cables that came with the motherboard. There are two IDE cables - one for the optical and hard drives, and one for any floppy disk drive, which is smaller. There are also SATA power and data cables, and some kind of tiny power adapter I'm not familiar with.

Before we put in the motherboard, we need to fit the metal frame we mentioned earlier into the back of the tower. Otherwise, to do it later, we'll have to remove the motherboard. And properly fitting in the motherboard is a great deal of work, so we don't want that.

Since there is a metal bracket where the metal frame needs to go, we have to remove this metal bracket. The idea is to break the small bridges between the metal bracket and the back of the tower; a tool can help here, unless you want to try thumping at it with your fist. Once the metal bracket is removed, carefully push the frame into its place (and make sure it is the right way up).

Step 4: Install optical drive(s)

We are now going to install the DVD drive into the tower. If you look at this photo, the optical drive needs to go into the top-right section of the tower. There are four slots for optical drives; which one you use doesn't really matter.

The drive is shown above. The front (left photo) is the tray you will see at the front of the tower. The back (right photo) must be connected to the motherboard using SATA cables. The right photo clearly shows the SATA slots (ignore the white thing with pins... that's not one of them). SATA slots are L-shaped. The longer one is for power; the one on the right is for data.

To work comfortably, I decided to remove the front panel of the tower. It is possible to install the drive without removing the front panel, but it's easier to work if you remove it. Removing it is a troublesome task though; you have to find the plastic thingies that fix it to the rest of the tower, press them and push them outwards.

Once you've removed the front panel, you will see something like in the middle photo above. There are several metal brackets for unused optical and floppy disk drives. We can use the top slot without breaking any metal brackets, but in case we want to install any further drives, we need to break off a metal bracket by twisting it to and fro.

There are also the plastic brackets on the front panel. These can be removed, but should be kept for future use (in case you remove a drive and want to close the slot against dust).

Now we can slide the drive into its place. We could have done this without removing the front panel, but trying to slide it in from the back is a difficult and clumsy process.

Check that the drive is at the right depth by fixing the front panel back in place. When it is in the right place, fasten the drive to the chassis with screws on both sides.

Note: the left photo above has nothing to do with the optical drive as such; it simply shows the card reader and some of the front panel connectors attached to the power button and other parts of the front panel.

Step 5: Attach CPU with heatsink and fan onto the motherboard

Now we have to put the CPU into the socket on the motherboard, and the heatsink/fan on top of it.

The bottom of the CPU, as you can see, is an array of pins that fits into the socket. It is important that you note the arrow in one of the corners; that shows you in which direction to place the CPU into the socket (the socket on the motherboard should have a corresponding arrow).

Place the CPU gently into the socket, making sure that the arrow on the CPU corresponds with that on the socket. Lift the lever beside the socket to a 90-degrees angle. You should notice the CPU sink deeper into the socket. Then you can lock the CPU firmly into the socket by putting the lever back down. Now it is time to put the heatsink/fan onto the CPU.

The heatsink is made up of a series of parallel metal bars that channel heat from the CPU onto the fan. In order to effectively conduct heat between the CPU and the heatsink, a thermal paste is used. This is the grey area in the top-right photo above. This paste will stick onto the CPU in order to conduct heat to the heatsink.

Remove the plastic cover and fit the heatsink onto the CPU. You should feel it stick to the CPU; this is something totally normal. The heatsink should have some mechanism that fastens it to the retention slot on the motherboard; make sure you apply this mechanism. Some heatsinks may only fit into the retention slot in one particular way, so if you're unlucky, you may have to pull off the heatsink (with a little effort) and turn it around. The photo on the right shows the CPU after the heatsink has been removed; basically it's covered with the grey thermal paste. While removing the heatsink will do no harm, it's not recommended to do this often; if enough of the thermal paste is lost, heat might not be conducted properly between the CPU and heatsink.

Once the heatsink is fastened in place, you can fit the CPU fan's power connector to the corresponding slot on the motherboard, which should be labelled something like CPU_FAN1.

Step 6: Installing RAM

Above is the piece of RAM I've used in this PC. It's a long strip of circuitry than fits into one of those long yellow slots on the motherboard, as we've seen earlier. Those slots, by the way, are called DIMM slots.

You will notice a notch among the connectors at the bottom of the RAM. That notch isn't exactly at the centre, so you can't go wrong when you place the RAM in the slot.

Installing RAM into the DIMM slots can be one of the most frustrating parts of PC building, if you don't know how to do it right. The procedure is as follows:

  1. Open the plastic thingies that hold the RAM in place
  2. Place the RAM into the DIMM slot at an angle (left photo above)
  3. Close the plastic thingy on the side where the RAM went in
  4. Push the other side down into the slot (middle photo above, but the right plastic thingy should be closed)
  5. Close the second plastic thingy to hold the RAM in place

Step 7: Installing the motherboard in the tower

Before screwing the motherboard to the chassis, the first thing to do is to actually place the motherboard in the tower and find the right place for it. Hold it by the CPU fan to avoid touching circuitry, and push it in so that the ports on the side of the motherboard come out from the corresponding slots on the back of the tower (photo above, left).

Align the holes in the motherboard (for a micro-ATX motherboard like mine, there should be 6 of them) with the respective holes on the chassis to see that you placed it right. These are the holes you will use to screw the motherboard.

Now before you grab your screwdriver, heed this one warning. You must never screw the motherboard directly to the chassis. You need some spacers so that the pins on the bottom of the motherboard will not touch the chassis. Otherwise, you can literally screw the motherboard. I did this with the first PC I built, and then wondered for three days why it wouldn't power on... I'm lucky I didn't fry the motherboard.

The spacers will normally be screws shaped like a hexagon. You screw them into the chassis, and screw the motherboard into them; like this the motherboard is spaced away from the chassis. In my case, this particular tower had no spacer screws, but the chassis itself provided the spacing needed (the holes for the screws were on a kind of bump in the chassis). So strictly speaking, you can, under rare circumstances, screw the motherboard to the chassis. But if you do, always look at the other side of the tower to see that the pins underneath the motherboard aren't touching the chassis.

Now you can go ahead and put screws into your motherboard. Note: the thing in the left photo above isn't a spacer... it's just a screwhole that fits in the chassis.

Step 8: Installing PCI cards (optional)

This is a network card. The bottom part fits into a PCI slot on the motherboard. The long part on the left is what appears on the back of the tower, and contains any ports the card may have.

To install the card:

  1. Using a screwdriver to remove the screws, remove the box that keeps the metal brackets in place.
  2. Loosely place the card into the PCI slot to see which metal bracket it corresponds to.
  3. Remove the corresponding metal bracket by twisting it to and fro.
  4. Place the PCI card firmly into the slot.
  5. Screw everything back on.

Step 9: Installing a hard disk

This is a hard disk. As with all components, always avoid touching it from the circuitry. The large circular part shows where the actual disks are; the circuitry controls the heads that access the disks.

The photos above show where the hard disk goes in the tower. There is a rack purposely for hard disks near the front side of the tower (the bottom part... the top part is for optical and floppy drives).

Slide the hard disk into place and fasten it tightly with screws on both sides. Be sure to use the right screws; they are different from those used for optical drives.

Step 10: Connecting the connectors

This is the last step: when we actually connect the last few things between the motherboard and the components. Your motherboard's manual should have a diagram showing you where to connect these connectors.

Above, we are connecting the PC speaker.

Here we're trying to give power to the motherboard. The power supply should have a couple of special connectors which give power to the motherboard. The second photo above clearly shows a square white 2x2 slot on the left and a rectangular white 10x2 slot towards the centre. Those are used to power the motherboard.

The 2x2 slot is called an ATX 12V Power Connector, and is actually used to power your CPU. The 10x2 slot is really a 12x2 slot, because the last 4 holes are covered by a sticker. As you can see, the power supply's connector for this 12x2 slot comes in two parts - a 10x2 and a 2x2 connector which fit next to each other and together make up a 12x2 connector. You can't plug it in the wrong way if you wanted to because the holes aren't exactly square.

There should be a separate connector for the ATX 12V Power Connector. Unfortunately, my power supply didn't have one, so I had to change the power supply.

Step 11: Changing a power supply

Changing a power supply is very simple. To remove your power supply, remove the screws on the back of the tower that hold it in place, and slide it out.

The photos above show the brand new power supply. The left photo shows the box, which is a nice display of fine Englandish with its "extremely silence". The middle photo shows the bunch of wires coming out of the power supply. Most of the connectors coming out of the power supply are large white blocks with 4 pins. These are called molex connectors and are used to give power to tower fans, IDE drives, and possibly any light around your power button.

The right photo shows the power connectors and also the voltage selector. It is very important that you set this correctly according to the voltage level in your country; setting this wrongly could fry your PC.

Simply grab the new power supply, slide it in where the old one was, and secure it with screws.

Step 10: Connecting the connectors (revisited)

Now that the power supply permits, you can fit the ATX 12V Power Connector into the relevant slot on the motherboard.

The connectors from the front panel also need to be connected. The photo above on the left shows the USB connector. The tiny 2-pin connectors in the photo on the right fit into a block of pins on the motherboard called the system panel. The system panel is where you connect the power button, power LED, hard disk LED and reset button.

The LED are just little bulbs. You can connect system panel connectors the wrong way without any harm; they just won't work. So if your PC doesn't power up, you probably connected the power button connector the wrong way. Or if the hard disk light doesn't work... well, you get the idea.

The photos above show the SATA cables being connected. I was lucky enough to have a SATA connector from the power supply, which also meant that I bought another cable for nothing! If you don't have SATA connectors from the power supply, or don't have enough, you will need a molex-to-SATA converter (second photo above). Connect both power and data cables to both drives and you're done.

If you have an IDE drive, the procedure is obviously different. Connect one end of the IDE cable to the IDE slot on the motherboard, and another end to the IDE slot on the drive.

Above, we are giving power to the fan on the back of the tower. Chassis fans normally have two molex connectors - one which is female (i.e. its pins are actually holes) and one which is male (i.e. normal pins). This is useful because you can chain your molex connectors through the fan to avoid wasting molex connectors from your power supply.

Step 12: Testing and troubleshooting

When you're done with the connectors (and don't forget the CPU fan's power connector if you didn't do it already), you can try powering on the PC. Make sure you switch off the power from the wall outlet first (left photo above). Connect the cables you need to the back of the tower (minimum: power cable and VGA cable) (middle photo above). Then turn on the power from the wall outlet, switch on the power supply from the back of the tower (if the power supply has a switch), and power on the PC.

Leave the tower open when you power it on the first time. If it doesn't power on, you will need to mess with its internals again.

In the photo above (right), you can see that the PC powered on but the monitor received no signal. In such a case, or if the PC doesn't power on at all, you will need to do some troubleshooting to try and figure out what you did wrong. In my case, the RAM was defective. The PC speaker may play some beeps if something is wrong with the hardware.

If you have problems, your best bet is to look on the internet for clues as to what might have gone wrong, or take the PC to someone qualified. Below is a list of things that might have gone wrong...

If your PC didn't power on, it's probably because...

If the monitor receives no signal but the PC powers on, it's normally caused by faulty RAM. However, do check the obvious and see that the VGA cable is properly connected at both ends.

Once the PC powers on and the monitor receives a signal (left photo above), you can proceed to close the tower. Fit the hooks on the side panels into their respective slots on the top and bottom of each side of the tower, and slide the side panels into place.

You can now pop in a CD of Windows or Linux, and proceed to install the OS and software you want.