I don't know how to solve your problem (sorry), but I will say this, I had to reformat my computer because I somehow became infected by "virtumonde" which avast just let right in through a torrented photoshop install. AVG on the other hand gave me a warning about the install and even told be what it was infected with; I've been clean for a while subsequently.
Avast's free version seems like something they cobbled together to look altruistic - AVG's free version is on the same par with its 'pro', albeit missing a few valuable features. I'd recommend comodo firewall as well, but I had some gaming issues with it and online gaming protection programs (xtrap, gamegaurd, etc.); if that doesn't worry you then it's one of the best firewalls around.