Warning !! AVG virus scanner removes critical Windows file

An update for the AVG virus scanner released yesterday contained an incorrect virus signature, which led it to think user32.dll contained the Trojan Horses PSW.Banker4.APSA or Generic9TBN. AVG then recommended deleting this file; this causes the affected systems to either stop booting or go into a continuous reboot cycle. So far, the problem only appears to affect Windows XP, but there is no guarantee that other versions of Windows don’t have the same issue.

Both AVG 7.5 and AVG 8.0 were affected by the update; a revised signature database has just been published that corrects this issue. People that have removed the user32.dll can either boot from their original Windows CD and choose the repair option, or use another CD to boot from and restore the file from C:\Windows\System32\dllcache. If you happen to need a bootable CD:
AVG claims to have approximately 80 million users worldwide; there is no official reaction on the AVG website yet, but FAQ item 1574 in their support section covers a “False positive user32.dll” and offers some advice on restoring your system using the Windows Recovery Console.