If AVG said it removed it, then unless it comes back, I think you'll have to take it's word for it, MB, although one I had recently managed to lodge itself in the System Restore folder, which meant it kept coming back.
Windows prevents outside programs, including antivirus programs, from modifying System Restore. Therefore, antivirus programs or tools cannot remove threats in the System Restore folder. As a result, System Restore has the potential of restoring an infected file on your computer, even after you have cleaned the infected files from all the other locations.
If the trojan reappears, MB, disable System Restore, which clears the hidden folder, then run AVG to remove the infected file. Disabling System Restore will remove the potential to roll back the machine to a previous state, but is the safest way to remove a threat contained therein.
To disable System Restore, right click your My Computer desktop icon, and select Properties, then the System Restore tab. Untick the box, to switch off System Restore. Don't forget to enable it again, once you have cleaned your machine.