Demonstrating quite clearly why you should never jump straight on an update the moment it's released, and that good backups are imperative, the latest update to AVG's free antivirus offering prevents Windows 7 64-bit from booting after a forced post-installation reboot cycle. The 271.1.1/3292 (432/3292) definition update, which requires users to reboot their PC after installation, blocks Windows from booting properly and throws up a c0000135 blue screen of death, requiring that you take recovery action.
AVG as you might expect, have promptly pulled the update and included instructions for use of the AVG Rescue CD/USB, which allows you to simply go into the system drive and rename the offending AVG files so they don't play a part in the Windows boot cycle. Of course you could enter into Safe Mode and remove the offending piece of software, and while there, why not install our current favorite free antivirus solution, Microsoft Security Essentials?AVG Free update cripples Windows 7 64-bit
Fuente: Download Squad