Microsoft Security Essentials, I run it on all of my PCs now. Works perfectly, and very good detection rate. (Some false positives, but still very worth it....and free too.)
:goodjob:
Never even had any false positives, it is easy to forget that it is there sitting in the background protecting the computer.
Not to thread jack but:
I'm currently using AVG (Free), would Microsoft Security Essentials be worth upgrading for?
I will also point out that it is incredibly weird seeing people recommend Microsoft software.