I would uninstall the new products for now, go to
http://www.malwarebytes.org/ and dowload and run the free anti-malware tool.
I would then re-download Spybot and run that as well. Ensure you are updating these producs regularly - and you should be connected to the Net when you first run these products so that they can update themselves.
They are good at identifying and removing viruses, trojans etc...
The other thing to try is in your system tools. You could try a system restore where you take the PC back to an earlier date - say a month or two ago - when you know it was working well.
So Start menu, Programs, Accessories, System Tools, System Restore.
Once things look good again - do reinstall protection. AVG is good, it's probably just your other problems that are getting in the way.