Thanks for the reply MCT I'm using the [shell] section to set the default user theme, so that works fine. However what I need to do is change the applied theme based on AD site. I could do this using group policy, but that would mean a new GPO for each theme and there are quite a few so I want to avoid that if I can. At the moment on win2k I have a set of scripts which run post sysprep and effective determine the AD site then apply an Appearence Scheme based on that site. Unfortunatly Schemes don't seem to work the same way in XP so I'm using themes instead. There must be an API call that applies the scheme when you click 'Apply', but I don't think its documented anywhere. When you look at the changes to the registry after you apply a theme, all Windows does is change the colour, screensave.exe etc reg keys with the values stored in the theme files. I've not really messed around with themes before but I was hoping they would be a bit more sophisicated than big .reg files! Anyway, before I set about writing some code to parse the theme files and apply the setting I want, if anyone has any ideas I'd appreciate the help!