Does anyone else use Shutdown.exe?

I would like to use this in conjunction with the windows scheduled task agent to shut down my machine as an automated process.

Ive used it on my machine (WinXP home, Full Version) but am having problems with it not completely shutting down, when initiated.

What it does do when it shuts down, is move to the 'you can now power off' screen (i never thought i would see that again, post win98!).

I am aware that there are command line switches when using this at a dos prompt, but am unsure if any of these can solve the problem.

Shouldn't shutdown.exe completely shut down the PC, rather than leaving it on awaiting the off switch?

Is there somthing within the power management that i am missing?

Please help and many thanks for you input.