I get this question all the time, Daniel, and in fact I'm facing the same situation myself: my three-year-old desktop has gradually gone from speed demon to slug. Windows takes several minutes to finish its boot machinations, file searches take longer than they should, and Firefox suffers from general "slowishness."

Why does this happen? Simple: over time, Windows accumulates various OS detritus that's not unlike the plaque that builds up in your arteries. Alas, the computer equivalent of a bypass or stent won't do the trick: you need to take more drastic measures, meaning wiping the hard drive and reinstalling Windows.

I know: ugh. It's a complex, time-consuming task, one that can easily consume an afternoon--if not an entire weekend. On the other hand, it's cheaper than a new computer, and nearly as effective.

Just a few weeks ago, PC World's Lincoln Spector wrote an extensive, invaluable guide to the process: . I'll be referring to it myself when I do my reinstall over the holiday break.

I anticipate hours of hair-pulling work. But when it's over, I know my quad-core HP with 6GB of RAM and 1TB hard drive will run like the rocket it is, not the turtle it's become.