Your computer switches to a screensaver after it has been idle for a specified period of time. Most screensavers occur after a few minutes of inactivity, but you can change how long it takes for the computer to switch on the screensaver. Most screensavers are simply pictures or animated sequences that the computer comes preloaded with, but some people would rather have a home video play on their computer for a screensaver. MP4 is a popular video format that a lot of people use for their videos, and it's simple to make a screensaver from an MP4.
Download and install the Microsoft Video Screensaver program (see Resources).
Launch Microsoft Video Screensaver by clicking on "Start," "All Programs," "Microsoft Video Screensaver."
Click on the "..." button in the configuration window. Use the window that appears next to point the program to your MP4 file. Then click on the "OK" button to find your MP4 file.
Customise the settings for your screensaver as you desire. You can set the video to loop and play full screen, among other options. When you have everything set as you want it, click on the "OK" button and close out of the configuration window.
Wait for your video screensaver to start playing. It will start after the preset amount of time.