I don’t use any of the windows protection programs instead of the firewall because I don’t trust them. In all my years, I’ve never ever had a virus penetrate my system with AVG free edition (granted I got them, but they were all caught immediately). I would recommend trying that. But if you don’t notice any problems with your system, it could be that its not a virus at all and your windows one care just recognized it wrong or is being overly cautious (thats what windows does).