Anyone using avast! antivirus might start getting a crap-load of false positives starting to happen when they receive the latest program update (possibly virus definition update?). Mine's just started detecting trojans inside MANY different applications I have installed that I know are perfectly clean. If you get a popup mentioning a program update, I'd decline doing so until it's fixed. I'm currently running version 4.8.1368 which seems to be the culprit.
There's even reports of it completely crippling machines by preventing them from starting up correctly. I'd suggest disabling the standard shield permanently until a fix is issued.
Be warned DO NOT allow avast! to delete any of your files, it seems something is seriously wrong with the most recent program update. Only solution at present is to terminate the standard shield until a fix is forthcoming.