Microsoft has released an update for Windows XP for the "stop 0x7e in aec.sys" problem on computers that running Windows XP Service Pack 2.

Install this update to resolve an issue in which you receive a “stop 0x7e in aec.sys” error message on a computer that is running Windows XP Service Pack 2. The error may occur during startup, or after the system has started. AEC.SYS is the acoustic echo canceling driver. After you install this update, you may have to restart your computer.

Update for Windows XP (KB900485)