There’s a small utility called “SHUTCMD.EXE” included in the Windows NT Resource Kit that can be used to shutdown or restart a local or remote computer.
For example, you can shutdown the local computer by running:
to shutdown a computer on a network (“SYTEM1” being the name of the system to be shutdown):
SHUTCMD \\SERVER1 /Y
to shutdown a remote computer connected to the Internet (“127.00.22.12” being the IP address of the computer you want to shutdown):
SHUTCMD \\127.00.22.12 /Y