Paul Boutin: Virus-proof your PC in 20 minutes, for free:

“So I whittled the world of options down to three steps that, on most PCs, can be done in less than 20 minutes. (Once you’re done, you’ll need to run some programs that take longer than that, but there’s no need to sit and watch.) Just as important, they’re all free, thanks to a mix of promotional offers and hacker idealism. Some of these instructions might seem obvious, even dumb, but I was surprised to find that many of my friends’ PCs had missed one or another of them. Any computer user who got hit by the Sasser worm hadn’t bothered to do the second step. Do all three, and you’ll be protected against the most common infections and still be left with time and money for lunch.” (Slate)