You should *NOT* be paying a monthly fee for any type of virus program...there are just too many free/open source options for you rather than pissing your money away (especially on stuff that mysteriously fills your HD). I've used AVG in the past, but I switched to clamwin (
www.clamwin.com) about a year ago, and everything's been peachy since then. I set it up to run virscan's in the middle of the night and send me an email if it finds anything...pretty sweet.