Where did you install AVG at? You may have picked up some malware from the download that is causing the problems, or it's a bad version of AVG.
Even if it isn't from the AVG download, obviously AVG hasn't been able to stop it, so you'd want to get rid of it anyway.
What I would personally do is cross it off my list and find another anti-malware that might be able to fix my computer, and try that. I use Trend Micro, but you have to pay for it, which you might want to do if you have the option. However, they do have an online scanner-
http://housecall.trendmicro.com/
I would try running that scan a few times-- it runs it over the internet so it will be slow and take a long time, but I'd say it's worth it. However, if you don't come up with anything the first scan there's obviously not much you can do with a second or third scan.
