Anti-spyware is included in win 7, not sure about vista as I've never used it. (it's not all that good though) The way hackers pick apart all of M$ operating systems, an included anti-virus would probably only be as good as the already included firewall, and they have never been very good, let alone very effective. Adding an anti-virus would only contribute to bloating, and probably not be all that secure, in my opinion.