[link|http://www.microsoft.com/technet/treeview/default.asp?url=/technet/security/tools/Tools/mbsahome.asp?finishurl=%2fdownloads%2frelease%2easp%3freleaseid%3d37761%26redirect%3dno|Microsoft Baseline Security Analyzer]
Scans your computer, checks to see what your service packs are, and tells ya how to fix it all.