The best way to keep your computer free of windows malware, viruses, trojans, adware and spyware is to not install windows :elvis:
Linux with wine works for all but newer games. If you must install windows, keep it on a seperate partition and only boot to it for games, don't web browse with it at all or the very least you can.
Works for me.
:idea:
that's basically my solution too

however, for those times when I go into my multi-boot windows system I just discovered
Wise Registry Cleanerit's also available in a portable version
http://portableapps.com/apps/utilities/wise-registry-cleaner-portableuseful for when your windows system is acting weird and you need to clean stuff up with a drive that hasn't been affected.
the Wise app seems to get rid of even more of those stupid temp files windows loved to collect (than crap cleaner does)