dreamscene_waterfalll DreamScene was a feature in Windows Vista Ultimate which allowed you to set a video as your desktop wallpaper. The feature, however, has been removed from the upcoming OS Windows 7 in favor of the Desktop Slideshow auto rotator. But don’t be dismayed – there is, in fact, a hack that allows you to re-enable DreamScene if you so desire.

Just follow these steps:

1. Download the file Windows7-DreamScene.exe (mirror). There’s also an alternative called Windows7-DreamScene-Enable.exe which doesn’t require you to have Admin Rights. 

2. Run Windows7-DreamScene.exe as Administrator. It will copy DreamScene.dll to %WinDir%\System32 folder, DreamScene.dll.mui to %WinDir%\System32\en-US folder and add the required registry keys and values. Then it will then automatically restart Explorer.

3. The installer also creates a Windows DreamScene folder in %WinDir%\Web\folder. You can place any video file that you want to set as DreamScene background wallpaper here.

4. To set a video clip (.WMV or .MPG) as your background, right click on the file and choose “Set as Desktop Background” from the context menu.

That’s it! Because DreamScene isn’t officially supported in Windows 7, you won’t find options for configuring it in the Personalization and Desktop Background configuration page. However, all the DreamScene features including Play, Pause, and audio are supported.

(Thanks to MyDigitalLife for this info!)