There are a number of threads on this but I just bumped this one I'm going to give you a link for that has many good suggestions on it. Don't stop at the first post, keep reading.
Is there a thread or list on Cnet of the best programs to run to keep my system clean?
I just bought a new laptop and desktop that I want to start off using the right protection for all viruses, adware, parasites, etc....
I have used Norton System works, Ad-aware and Spybot S&D in the past.
Thanks for your help!