This will show you how to create a
Remote Shutdown Dialog shortcut to be able to shutdown or restart one or more remote networked computers
\\ComputerName all at once.
You must already have
administrative privileges on the networked computer to be able to do so.
If you’re on a home network, the best way to do this is to make sure all computers are in the same workgroup and that they all have at least one Administrator account with the same user name and password.