I use Window ME and used to use AVG but, as AC indicates, AVG 8 won't run under ME. (Although, contrary to AC's concerns, attempting to install it can't do any harm because the installer checks the OS and simply refuses to go any further).
So I've switched to Avast! (which does run under ME) with no problems: http://www.avast.com/
I am merely suggesting the one i use , if you are expected to investigate with a fine tooth comb like some sort of detective then this is not the site to post on !!