Before you begin
When you buy your own components, make sure to get parts that your PC's power supply can support. Some items will use more power than the ones they replace; others will use less. My Dimension 8300 has a full-size tower case with a 250-watt power supply, which should be plenty for my new components.
All the prices mentioned in this story are actual prices that I found at online retailers -- often considerably less than the suggested retail price. But be warned: Prices can fluctuate wildly, so it pays to shop around. My favorite way to find the best price is to use Google Product Search, which lists online retailers' prices for the item you're looking for.
As part of the hard drive upgrade, you'll need to install Windows on the new drive, so now's the time to find the Windows CD that came with your computer. If you don't have your original OS disc, try calling your PC's manufacturer -- some of them will mail a replacement disc to you for a nominal charge. Otherwise, it might cost $100 to buy Windows XP, which will blow your upgrade budget. In that case you might be better off buying a new PC.
It may sound silly, but it's important to find a good place to work. Shoot for a location that has a table big enough to spread out your open PC and parts, and where you won't be interrupted or stressed if the upgrades take longer than anticipated. Forget about the kitchen table -- if you're not done at dinnertime, there'll be problems.
Some people insist on wearing a grounding bracelet or antistatic gloves to protect the system against static shocks; either will cost about $5 at a variety of online stores. On the other hand, I've been doing this sort of thing for 20 years without wearing either item, and I've never had a problem. It is, however, a good idea to touch something that's grounded to remove any static charge you might have before you touch anything inside the PC case. A metal plumbing pipe or radiator works well.
Backup battery: Energizer CR2032 ($2)
RAM: Kingston 1GB 400-MHz DIMM module (2 @ $40 each)
Hard drive: WD Caviar Black 500GB ($65)
External hard drive enclosure: Acomdata Samba ($29)
Cooling fan: AOC FC-2000 System Blower ($7)
Video card: Nvidia GeForce 6200/256MB ($40)
Audio card: Creative Technology Audigy SE ($25)
TV tuner: AverMedia AVerTVHD Volar ($40)
Webcam: Logitech QuickCam Connect E2500 ($30)
Keyboard and mouse: Microsoft Wireless Media Desktop 1000 ($40)
AA batteries for wireless keyboard and mouse (4) ($5)
Task 1: Open case, clean up, and replace clock battery
Time: 15 minutes
The first step is to unplug the system, open the case and lay it on its side. Gross! If your PC is like mine, inside the case is over four years of accumulated dust, cobwebs, dirt and more than a few dead insects.
With a can of pressurized air, gently blow out all the garbage, paying particular attention to the processor's heat fins, which in my PC's case are clogged with debris. (The system has a habit of overheating, and that is probably why.) A word of advice: You might want to wear a dust mask for this task -- who knows what's in there?
Now that you can see what's where inside, it's a good idea to locate the major parts you'll be dealing with: system memory modules, hard drive, audio and video cards. My system also has a FireWire card, which I won't be touching, and a modem card that I've never used -- I'll toss that out.
Before moving on to the fun stuff, take a minute to replace the system's backup battery. It's a standard watch cell that lets the PC keep track of the time and date when it's off, and it generally has a life of four or five years.