Gotta agree with Labob on this one.
I've used some of the leading AV solutions in paid and free editions. The industry will say AV Program A is the best this year, then AV Program B is best the next. So I guess we're supposed to hop on that merry-go-'round if we want to be protected to the ultimate level, right?. Well, then along can Security Essentials. Free and provided my Microsoft. I don't know about you, but as an MCSD, I'm well aware that documentation on all the hooks into Windows are not public knowledge. The only conclusion is that there is only one source that is uniquely positioned, and with full knowledge of how best to protect a Windows system. That's Microsoft. And did you get the part about how MSSE is FREE? The Antivirus merry-go-'round came to a grinding halt for me at that point. Oh, and BONUS - it's about the fastest, most resource friendly AV program out there. And oh yeah, did I mention it's FREE?
Go get you some.