Changing powersaving setting for all users

I've got a PC used by about a dozen different people each with their own log on, and for some unknown reason the power saving settings for all user have been changed from never to sleep after15 minutes.

 

This is causing problems as we use an application that requires constant network communications and each time the power saving activates it locks the desktop and breaks the network connection just long enough to crash the application and to loose any data that was on it which hadn't been saved.

 

I'm using ZEN desktop and Novel on top of Windows XP SP2, and am having to log on to each user individually in order to change their settings back to what they are supposed to be. Is there a registry setting that I can tweak or a checkbox that I can tick to propogate the correct setting across all users on a PC?

 

Better yet, does anybody have any idea what happened to make the power saving settings change like this for everybody?