Instructions
Click "Start" on your computer. Click "All Programs," then "Media Center."
Turn on your Xbox 360.
Press the guide button and navigate to "My Xbox." Choose "Windows Media Center." Write down the activation key.
Click "Tasks" and "Add Extender" on your computer. Type in the activation key. This will connect your PC and Xbox 360. The Xbox 360 will launch a browser where you can find all of the media files stored on your PC. Press "A" on any video you want to watch.