AVG Update Borks Windows 7, Here's How You Can Fix It

If you're an AVG user having trouble booting into Windows 7, you have our condolences. Perhaps it might come as a small consolation that you're not alone, and chances are you did nothing wrong. The culprit, AVG says, is that the latest virus database -- 271.1.1/3292 (432/3292) -- released earlier this week is bricking systems with a STOP code.

AVG has since pulled the update, but that doesn't do you any good if you've already installed it. In that case, AVG recommends booting into Safe Mode and running System Restore to a point in time prior to the update. Barring that, AVG says to do the following:
  1. Find a working computer and create an AVG Rescue CD, if you didn't already, and use it to boot into your computer.
  2. When the Rescue CD is launched, navigate to Utilities > File Manager.
  3. Navigate to the mounted system drive (usually /mnt/sda1).
  4. Within this drive, navigate to the /Windows/system32/drivers/ folder and rename (using the F6 key) all files starting with avg (such as avgldx86.sys, avgtdlx.sys, and any others you find) to back them up. You can do this by changing their file extension to .bak.
  5. Remove the Rescue CD and reboot your PC. Your system should now boot with AVG disabled.
  6. Re-install AVG.
Alternately, some AVG forum members recommend booting into Safe Mode with a command prompt and renaming/removing the AVG program folder. Doing so should allow you to boot normally, after which you can then run the repair installation of AVG.

Note that this issue only affects 64-bit versions of Windows. If you're running a 32-bit OS and can't boot up, the culprit is likely something else.