Alright, for those of you who don't know what Dreamscene is, it's an addon in Vista Ultimate that allows videos to be played as a background image.
Windows 7 Ultimate doesn't have it, due to the "Ultimate Extras" package being removed.
BUT...this trick here will allow you to have Dreamscene on Windows 7:
This goes for EVERY version of it.
There's more; if you run Vista and you don't have the Ultimate package, that's also possible to have Dreamscene in other versions. Check here:
Dreamscene is in fact much more flexible that I thought.
If you use the first link to enable Dreamscene in Vista, every time you restart, you will need to relaunch the installer, while in the link mentioned for Vista, you won't.