If there are any issues with removing AVG normal way please use AVG remover tool:
Sometimes it is neccessary to run the tool multiple times.
Two different computers, one vista home, one premium, neither AVG would uninstall (took me two days to get that far)Finally deleted AVG from Program Files in safe mode (partial) and then both would boot. Many, many hours in safe mode and all the time it was AVG. Exported the registry and searched out the rest of avg and now have two other anti virus programs. Both work fine and hope this helps some one else. As for the folks at AVG, I wish I could bill them for a fraction of the time and frustration.