shutdown pc by cmd

1 open cmd and type-
  shutdown -s -t 9   for shutdown (9 mean any second)
 shutdown -a     for shutdown stop


2   c:\>shutdown -m \\it -s

Shutdown - This is the command u use to shutdown/restart/etc
-m - It means remote computer.
\\it - This is the computer name which you want to shutdown
-s - You have to enter this command (-s = Shutdown, -r = Restart, -l = Logoff, -a = Abort shutdown)

You can use 'net use' command to see the computer names in your network.