Way to automatically shut down my 2950?

I have a Dell 2950 running Windows XP Pro SP3.

I have three 75Gb drives running as a Raid 0 and a fourth drive as my C drive. At the end of my work day
I need to move the video files from the raid to an external USB drive and then power down the 2950 to
conserve power.

Right now I'm having to come back to my office at night on order to do this.

Is there a way to set the system to shut down automatically after a certain period of time... say in 4 hours or at 9:00PM?

Thanks for any help you can provide.