Sometimes using a Antivirus boot/rescure disk is the best bet. That way you're not running an OS off of an infected disk. This also prevents the files on your HD from being "in use", which sometimes prevents healing or deleting of the files.
I am sure that AVG has the option to make floppies (at least it does during the install phase).
You'll probably want to make a spare set off of a "clean" pc if you're still having trouble.
