Windows 2000 & Windows XP built-in shutdown command can be launched from a command prompt or create a shortcut on your desktop to launch whenever you like.
Note: To see a list of all available options type SHUTDOWN /? from a command prompt.
This command starts a 30-second countdown for shutdown or restart which allows you to abort the process during that time (shutdown -a command). Using the -t flag allows you to set the time lapse in seconds.
To shutdown and restart
SHUTDOWN -r -t 01
To shutdown
SHUTDOWN -s -t 01
Related Links:
Microsoft Support
How to Use the Remote Shutdown Tool to Shut Down and Restart a Computer in Windows 2000

