I've had AVG ruin too many of my clients machines...
to recommend it. They didn't listen and SPLAT! They lost their machines, one after another. They listen to me now! At least with even an old version of Avast with the kernel NEVER updated. I've been able to completely recover most PCs. Especially enough to wipe and reinstall. Avast and SAS will take care of most(at least 97%) of the backup file infections after that.