I presume you are referring to the settings found in the ‘Power Options Properties’ dialog accessed by pressing the “Power” button on the ‘Screen Saver Tab’ in the Display Properties dialog accessed through control panel or by right-clicking a vacant spot on the screen and choosing properties from the context menu.
A – the avalable options in the ‘power options dialog’ are determined by the ‘computer’ value in ‘Device Manager’ on the ‘Hardware Tab’ of “System Properties”. If the computer is listed as “ACPI” then ‘Soft Shutdown’, ‘Standby’, ‘Hibernate’ values will be in the “registry”. IF it is NOT ACPI then those values won’t be available.
B – To push changes to 900+ systems as part of GPO or logon script would require that they all be the same model and series. [i.e. HP Pavilion 520n, 521n, 532n are close enough, but a520n, a620n, and a210n are not.]
C – If they are all the same model/series and all XP SP2 patched current, you can push a reg file to update the registry and set them all the same. PROVIDED you haven’t turned off ‘Remote Registry’, which is recommended.
D – I did not find an entry in GPO. The registry entry on my system (HP Pavilion a620n) is in HKEY_LOCAL_MACHINE the ‘Haredware’ section, ‘Description’ subsection, under “multifuntion adapter” item “3″ which is ‘APM configuration. [Automtic Power Management]. While I don’t know the specific bits in the data, I do know that it values do change correctly if this key is copied to an identical system.
Registry ‘Hacks’ are very powerful and correspondingly dangerous. Proceed with caution and best of luck.