I upgraded to the new AVG 8.5 free package and my PC suddenly decided it would take over 4 minutes to bootup and overall seemed very sluggish especially when opening a drive. I uninstalled it and downloaded the trial of Kaspersky AV but that demanded I uninstall my Zonealarm firewall. Next I tried the trial from McAfee but that quite frankly turned my PC into a treacle sponge so that got uninstalled as well:)
I'm going to try the well reviewed free offering Avast! next and if that doesn't work I'll try to get AVG8.0 again.