Even if you don't see the symptoms, your computer may be infected, because more and more spyware is emerging. Spybot-S&D is free, so there's no harm giving it a try to see if something has invaded your computer.

Spybot-S&D can also clean usage tracks, an interesting function if you share your computer with other users and don't want them to see what you have been working on. And for professional users, Spybot-S&D allows you to fix some registry inconsistencies and extended reports.