Microsoft Antispyware program - Just beware, it is still in beta and the last that I heard, it will be a program that Microsoft may actually SELL for money, not let use for free. But still a lot of time between now and then.

I use Spyware search & destroy and adaware to clean my system about once a week. I installed the Microsoft thing, but was really annoyed that even in the config I told it I did not want it running, it still was starting up automaticly as startup. (Which I use another program to disable it from automaticly starting up.)