How To Build an Inexpensive Desktop

This is an intermediate level computer article. I do not recommend that beginners attempt this project without some assistance. If you have never dared to open up your computer case to install a new drive or memory or a sound card or video card, you might chicken out halfway through the procedures. You would then have a bunch of expensive parts and no working computer, and you would probably blame me. I would really hate that, especially the part about blaming me. Note: I actually built a computer while writing this article to ensure I got the procedures right.

Still, building your own desktop is not quite as daunting as it sounds. You need to assemble the following components to assemble a functioning desktop:

• Case with power supply (400 Watts or better). Needs to be Micro ATX form factor for modern boards. Get one with at least 2-3 internal 3.5" drive bays, plus at least one 3.5" external drive bay and two 5.25" external drive bays. The cheap ones are light and easily bent, but quite functional. With the cheapest, you may need to buy a case fan. Look at the direction of airflow when mounting a fan. It should exhaust warm air from the case, not push air into the case. The fan will get power from a power supply connector or from the motherboard. Consult your manuals. For this article, I did not find a sale, so I bought a new case for $30 and a fan for $10.
• Motherboard and CPU. Buy them together at the same place, and make sure they are compatible. If your CPU does not come bundled with a fan, you will have to buy one. Most of today's boards have sound and network interfaces (and often graphics as well) built in. I tend to buy the CPU & motherboard bundled together. Really do your homework. Research motherboards to find what is most likely to fit your needs. I buy locally, and I buy things on sale, but that will be hard if you are not close to a city with decent competition among computer stores. Mail order is a decent way to go, but you have to be somewhat more patient. Actually, you have to be a LOT more patient. For this article I bought a motherboard bundled with a 3 GHz Pentium 4 CPU (with fan) for about $100. The board supports SATA and DDR2 RAM.
• RAM. Consult your motherboard manual. If you haven't bought the motherboard yet, but you have it picked out, you can almost certainly find the manual online. Buy the fastest RAM you can easily afford. It is best to stick with name brands rather than generic. And it is better to get more RAM rather than less. For this article I bought 1 GB of DDR2 RAM for $80 with a small rebate.
• Hard Disk Drive (HDD). These are incredibly inexpensive these days. I would not get anything less that 100 GB. Get a 7200 RPM drive with at least 8 MB cache for decent performance. If your motherboard handles it, you can also try a serial ATA (SATA) HDD. These take special cables and power leads, which are usually bundled with the motherboard if the board supports SATA. For this article I bought a 300 GB SATA drive for under $100.
• CD-ROM/CD-RW/DVD-RW. I would just go ahead and get a DVD burner. They are dirt cheap, and one drive can do all you will need. It will need a parallel ribbon cable. For this article I bought an 18X DVD-RW for $40 with a $15 rebate.
• Floppy drive. Optional. Nobody uses floppies anymore. I still recommend you install one in case you have to boot from floppy to flash a BIOS or something later. For this article, I did not install a floppy.
• Optional: For better video (and sound), get high-performance cards and bypass the stuff built into the motherboard.
• Operating system. Everybody uses Windows or Linux these days.
• Other additions. I started to add that you should have a reasonable supply of curses and epithets when building a computer, but my wife told me to leave that part out. These are, however, commonly-added components when building your own desktop.

Again, some level of computer knowledge is assumed in this article. If I use a term you don't understand, use your favorite search engine. The truth is out there.

Special considerations:

• Case: if you have to buy a case fan, buy a quiet one that still moves significant air. Look for something close to a 25 CFA rating for moving air and 20 dBA for noise. Case fans are the 80 mm size. The case needs USB ports on the front for easy access.
• Motherboard: It will be a Micro ATX form factor. Look for a fast Front Side Bus (FSB) of at least 800 MHz. Does the motherboard support dual core technology? Do you care? It should support DDR RAM or DDR2 and have enough slots for at least 2 GB.
• CPU: A new board should handle at least a 3 GHz Intel CPU or the AMD equivalent. Get a decent CPU-motherboard combination deal for the best price. At this writing, you should spend $150 or less for a combo. You have a choice of Intel or AMD CPUs. I am not going to tell you which is better. Do some homework. Google is your friend.

But enough preparation, let's start building. The only tool you will probably need is a cross-tip screwdriver and a pair of pliers.

1. Preparing the case. Take the case out of the box and take the sides off. Designate a place where screws go so you can find them later. Tower cases are prevalent these days, so I will assume that's what you purchased. Find the bag of screws that came with the case, and set it aside. There will be a bundle of power cables coming out of the power supply and some other wires or cables that extend from the front of the computer. Unbundle these wires and position them so they won't be in the way when you put the motherboard in.
2. Prepare the motherboard. Open up the box and set everything except the motherboard aside. Work beside the kitchen sink.
   • When working around computer components, static electricity is your deadliest enemy. In a perfect world, you would be working at a bench with a ground bus, and you would have a grounding strap on your wrist at all times. I deal in realities. I work in the kitchen. I don't go shuffling across a carpet before touching things. I ground myself by touching the stainless steel sink or faucet. I avoid touching any contacts on the components. And I haven't blown anything up with static discharge yet.
   • Take the motherboard out of its anti-static bag, but leave it on its anti-static mat. Avoid touching any metal parts. Touching contacts and traces may lead to later corrosion./li>

3. Mount the CPU. Take the CPU out of its box and look at the mounting instructions. They are usually pretty well written (unlike most computer components). If the CPU socket on your motherboard doesn't look anything like the one in the instructions, you have a problem. Solve it before continuing. The key to mounting the CPU is to follow the instructions exactly, and never force anything. If the CPU doesn't fit easily, you are doing something wrong. With just a bit of patience and attention to detail, you will get it right.
4. Mount the CPU fan. The same advice about forcing the CPU does not always apply to the fan. These are bulky and often do not clamp on as easily as the instructions imply. Don't use a hammer or a crowbar, and don't be ridiculous, but do not be surprised if you have to apply a bit more force than you thought you would. Make sure you are following the instructions correctly, and always work on the anti-static mat that came with the board. Don't muck around with the fan while the board is mounted in the case. You can bend the board and cause something to break. You will get the fan mounted after a short struggle. Plug the CPU fan power connector into the connector provided on the motherboard. It won't be far. Consult your motherboard manual if you can't find it.
5. Prepare the case for the I/O ports. Grounding yourself before starting, pick up the motherboard and put it inside the case in roughly the position in which it will be mounted. The I/O ports (connectors for printer, network, USB, etc.) will go to the rear of the case. The case will have cutouts for these, and they won't be quite right for your board. Look more closely, and you will see that there is a long rectangular cut that goes all the way around the case cutouts. You will have an I/O template made of shiny silver that came with your motherboard. It will exactly match the rectangular hole you are now going to create. Take pliers and carefully start prying and wiggling the metal until you break the case I/O template loose and remove it. Cheap cases have thin metal, and it bends easily. The original stamped template should break away pretty easily though, so removing it is not hard. What is more challenging is putting in the new template that came with the motherboard. It never just snaps in perfectly. Another caution: The I/O port cutouts all have these little thin metal tabs that partially block the openings for the ports. For the square connectors such as modem, network, USB, etc., these tabs are in the way and must be bent out of the way or cut off. Position the template over the motherboard BEFORE snapping it in the case to see which ones need attention. Carefully snap the I/O template in place and put the motherboard in its final position.
6. Mark the case for the motherboard standoffs. With a felt tip pen, mark the case so that you can identify each hole on the case that matches a corresponding hole for a motherboard mounting screw. Then, for each hole you marked, screw in a standoff from the bag of screws you got with the case. A standoff is a short, hexagonal brass cylinder with a hole at one end and a threaded shaft at the other. Screw the shaft into the threaded mounting hole in the case. Tighten with pliers. The motherboard will then be screwed to the standoffs. You must have every standoff in the right place; otherwise, you will short something out when you apply power. All those chips on the motherboard have smoke inside them. It is the smoke inside that makes the chips work, and if the smoke gets out because of a short circuit, they stop working.
7. Install the motherboard. Screw the motherboard down firmly, but do not overtighten or you will risk crushing the board. That would be a BAD THING. When the board is mounted, attach the power leads. Consult your motherboard manual for the location(s) of the power connectors (there will probably be two). Now consult your motherboard manual even more closely. You need to attach the leads from the front of the case to the board: power switch, reset switch, power LED +, power LED-, HDD LED, and USB. When in doubt about polarity (+ or -), assume that red wires are positive, and black wires are negative. Sometimes you may have problems hooking up these wires, and it can be very frustrating. This is the swearing part my wife made me leave out. You may want to ask for help from a geek friend if that happens. Luckily, it doesn't happen often.
8. Install the RAM. You can do this quickly and safely. See my article How To Upgrade Your RAM.
9. Install a floppy drive. If you decide to install a floppy drive, I already have an article on doing this: How To Install a Floppy Drive Into a PC.
10. Install a CD-ROM. As I already said, I would recommend a DVD burner instead. They hardly cost more than a CD-ROM. Remove a plastic panel cover from a 5.25" drive bay. Slide the drive in from the front, and screw it down so that the front is flush with the front of the case using the smaller diameter screws provided with your motherboard. CD-ROM drives use the same type power connector as IDE hard drives. CD-ROMs and most HDDs use parallel cables for data transfer. Nowadays, these cables are keyed so they can only be plugged in one way. Often, the connector at one end is blue. That end plugs into the motherboard. The other two connectors are for any other two IDE devices. You can have a maximum of 4 IDE devices: two on each IDE bus (and you have two buses on your board). Don't forget that there is an audio cable that runs between your CD-ROM and sound card (which for the purposes of this article is assumed to be on the motherboard).
11. Install the HDD. This article assumes you will have one hard disk drive. Get a large capacity, 300 GB or more. Slide the drive into an internal 3.5" bay from the back, and screw it down using the larger diameter screws provided with your motherboard. Connect the power and data cable as above for IDE drives. SATA drives have completely different power and data cables. If your case is new, it may have an SATA power cable. The case I bought is SATA-capable, and it came with an SATA power cable adapter as well as an SATA data cable. Not addressed in this article are other HDD configurations such as RAID drives. You will need to read your motherboard manual or do a search for more information if you want to put together a RAID array.
12. Other cards and devices. The built-in video, audio and network interfaces on inexpensive motherboards provide just basic functionality, so you may want to upgrade these, especially the video card. Modern ATX form factor cases handle AGP cards (for most video cards) and a number of PCI cards (the bulk of the slots on a motherboard). Most other devices such as printers, scanners, cameras, etc., are USB devices. Most cases provide at least two USB ports on the front of the case, and the motherboard usually has 2-4 more slots on the back. You are really at the point where you are on your own now. Customizing goes beyond the scope of this article.
13. Check everything. Are there loose wires that can get in the way of a fan? Is the RAM seated well? Is everything plugged in? It's time to plug it in, hook it up and kick the tires. Leave the case sides off for now.
14. Power up and install an OS. Put the OS installation CD in the drive. Hit the power button. No power? Did you flip the switch on the power supply on the back of the case? Are all the fans running? If not, shut down and find out why. For the first startup, enter setup. That is usually accomplished by pressing the Del key or F2. Watch your Power On Self-Test (POST) sequence. Is everything OK? Put the sides back on the case. Install your OS. Don't forget to have your motherboard CD available. You will probably need to install some drivers.
15. Pat yourself on the back. Yes, building a computer from components is a bit daunting, a bit challenging, but it is very rewarding, especially later when everything is really snappy, and you think about all the money you saved!