This post will help you to set videos as desktop background on your Windows 7 PC
Windows dream scene was a windows feature added in Windows Vista. It facilitates users to set videos as their Desktop background, but later it was removed fro Windows 7. But a simple registry tweak can enable this feature in your version of Windows.
To enable on your, just download the free tool from the link below, Give a Right Click on it and select RUN AS ADMINISTRATOR, and select enable to enable.
After this right click on and ".wmv" or ".mpg" video and select "Set as Desktop Background" and Enjoy!