Ultimate has stopped running dreamscenes

[nick160460]

any one out there with any Ideas why my PC has all of a suddun stopped running Deramscene's I have gone through :
Window Colour and Apperance -> Appearance and selected Windows Aero

Also looked into :Theme Settings
but WIndows Areo is not listed (should it be?) I've selected Windows Vista from the drop down list but dreamscene still not working

However my wife uses the PC as a seperate logged on user and dreamscene runs ok on her desktop

I've got all the updates etc new drivers for graphics card etc


please help