system
2
Search for the EXACT removal tool for the EXACT AVG version/edition at http://thewebatom.net/uninstallers/security-software/.
Reboot into Windows Safe Mode and run the removal tool. You might want to do the same for Avast’s removal tool from http://www.avast.com/uninstall-utility also from Windows Safe Mode.
In any case, please reboot in between runs of removal tools.
Download the latest stable Avast from the official site and try again.
Please report back.