For years I used to use Spybot and Adaware along with firewalls and various AV programs. I purchased and installed Kapersky anti-virus 2010 after seeing a 5 star review it claimed to do everything in one package. I soon realised that it was slowing my system down and giving false positives and I still managed to get infected with some crappy virus. I removed Kapersky and installed PANDA which I had used before. Just before Christmas, After cleaning the hard drive of my main computer and re-insalling windows 7, I decided to give microsoft's own FREE AV/security software a try. Well I think it's fantastic and long overdue. No need for any third party resource hungry stuff anymore! The only other system clean up program is one called CCleaner which I run manually every so often.