The reason antivirus suites dont see the virus is because the file attribute its files were set to system/superhidden.

So even if you set your folder view to Show hidden files, it would still not show up.

You have to enable showsuperhidden key in the registry then do a full system scan as that virus/trojan put files iside the windows directory and modify keys in the registry. Particularly the ShowSuperHidden key.

To modify that key;

Click "run" at the start menu, type regedit

the Registry editor will open.

Go to HKEY_CurrentUser\Software\Microsoft\Windows\Explorer\Advanced

on the left side look for the key ShowSuperHidden and set it to 0 (ZERO).

Close the Registry editor then on Folder options' View tab select Show hidden files. You may havee to reboot for the changes to take effect. then Do a full system scan, with your removable drives plugged in.

AVG should see it and clean it.