If you are running Vista or XP here is a free beta tool from Microsoft, it is already built in to Windows 7 have a look.
http://fixitcenter.support.microsoft.com/PortalHere is what Microsoft say.
Fix it Center finds and fixes many common PC and device problems automatically. It also helps prevent new problems by proactively checking for known issues and installing updates. Fix it Center helps to consolidate the many steps of diagnosing and repairing a problem into an automated tool that does the work for you.
