Instructions
Click the "Start" button in the lower left corner of the screen, then click the "Control Panel" option.
Select the "Home Group and Sharing Options" icon, then click the "Change Advanced Sharing Settings" link.
Locate the "Media Sharing" section, then select the "Choose Media Streaming Options" button.
Select the option to "Turn on media sharing."
Turn on your Xbox 360.
Navigate to the "My Xbox" menu, then select the media type associated with the file you wish to access from your computer.
Select your PC, then select the file you wish to play.