auto power down after inactivity windows xp

Have you looked at the power options? You can set XP to suspend or hibernate, but there's no full power down on inactivity.

There's at least two ways to get to the power options. Either right click a vacant area on the desktop, choose properties, then go to the screen saveer tab and click the POWER button, --- OR --- use Start/Control Panel and then select (1) in classic view go to power options or (2) in category view go to Performance and Maitenance and then power options.

In the laptop you can set it to hibernate after a certain inactivity time.
Regarding the desktop, maybe you can find a 3rd party freeware app that can do what you want.
I don't remember if this can be done by GPO, I'll check it.