Spyware: What It Is and How to Get Rid of It
Forgive the off-topic post, but most folks have 'spyware' on their computers. In fact, every time I use a PC at my in-laws I find their computers are so crammed with it they can hardly function. There's a good chance your machine has this problem too. Here's a great explanation of what Spyware is and how to get rid of it from the Wall Street Journal's Walt Mossberg.
http://www.smartmoney.com/mossberg/index.cfm?story=september2004