Forcing a remote computer to restart

Occasionally I find I need to reboot a remote computer. In my current situation the remote computer is Windows XP and accessed via VNC. However the VNC server will occasionally stop responding.

If the machine's IP address was 1.2.3.4 and I try:

shutdown /m 1.2.3.4 /r /t 1

it does not reboot the computer. Assuming there is nothing to save on the computer and I just want it to reboot and restart the services, I am happy to just kill processes until I hit something critical and it reboots.

However, if you hit the RPC process, you will be unable to send the command to kill more processes. So you have to be careful about which process you are killing. What I have found is killing the lsass.exe process will cause the computer to reboot. So issuing:

taskkill /im "lsass.exe" /s 1.2.3.4 /f

Will kill the lsass.exe proccess on the remote machine and force a reboot of that computer. The reboot will not be immediate. A 30 second countdown will happen as the system warns you a critical process was killed. However it will reboot the computer after the countdown is complete.