Q. You receive on STOP 0x0000007E BSOD on Windows XP when your keyboard class driver is configured in grandmaster mode?

If your Windows XP laptop has the Kbdclass driver configured in grand master mode, as in SMS 2003 clients, you may receive an error similar to:

Stop 0x0000007E (parameter1, parameter2, parameter3, parameter4)
SYSTEM_THREAD_EXCEPTION_NOT_HANDLED

To disable grand master mode for the Kbdclass driver:

1. Open a CMD.EXE window.

2. Type the following command and press Enter.

REG ADD HKLM\SYSTEM\CurrentControlSet\Services\Kbdclass\Parameters /V ConnectMultiplePorts /T REG_DWORD /F /D 0

Instead to this workaround, you can call Microsoft and request the 926238 hotfix.