[Kira]

I also recommend Ad-Aware; I've been running it for a couple years and I have no problems. A few words of caution, however: if you use Kazaa, you may have to reinstall it after cleaning your drive since it has built-in spyware. (Kazaa Lite, however, does not, and is better anyways.) Secondly, a friend of mine that I got to install Ad-Aware has found that when he runs it Ad-Aware tries to delete a file called mozz.dll that Mozilla uses. You just have to watch out for that sort of thing, and it doesn't take long to be able to recognize the files that you shouldn't delete when you run it. (With Ad-Aware, you can make a backup of the files first, so if you wipe something essential it's not gone -- this is a good idea for the first few times running a scan.)