The trick below lets you shut down XP really fast in just 1-2 seconds.To do this:
Press Ctrl+Alt+Del to fire up the Task manager.
Keep Ctrl key pressed.
Now go to Shutdown>Turn Off in Task manager while keeping Ctrl key pressed all the time.
Just keep holding the Ctrl key down till XP suts down.Shouldn't take more than a second.
Note: This trick won't harm your PC in any way.It is certainly better than turning of the power button directly!!