If you choose to use AVG, the best solution would be to check out their site to see if the latest update has been causing problems. I know they have a tech support section for the updates, I just don't recall the web address to it. If the update itself is bad then re-installing AVG could leave your computer even more vulnerable because it will be even more out of date.

FYI: AVG is a bit notorious for pushing out shitty patches which run the gamut from not working at all to thinking Windows is a virus and bluescreening the shit out of it. I left them because I no longer trust them to know the difference between a virus and something innocuous. And yeah, it's a pig too, just not as bad as McAfee or Norton. Those two are absolute bloatware.