The 0x7E stop error often occurs because of a timing issue in Windows XP and Windows XP Pro. Tjis error can occur during initial system startup or even once up and running after your Computer has been sitting idle for a while unattended. The result is typically a blue screen displaying a STOP 0x0000007E error in aec.sys. Complete error message might display something like the following: STOP 0x0000007e (0xC0000005, 0x00000000, 0xF8954080, 0xF8954384) aec.sys.
How to fix the STOP 0x0000007E error:
There is a hotfix patch available via Microsoft's Site for Windows XP that addresses this bug. The error is primarily caused by a timing error in the aec.sys file resulting in a blue screen of death crash.
You can download the HotFix directly from Microsoft HERE
More detailed information can also be found HERE