Instructions
Connect your Xbox 360 to your computer via Ethernet cable or wirelessly with the Xbox 360 Wireless Networking Adapter. An Ethernet connection requires the user to plug one end of an Ethernet cable into the console and the other into the PC. The latter option can only be accomplished if the computer also has a wireless networking adapter and the "Window Connect Now" software. Download and install the software off Microsoft's website if necessary. Then go to "Configure Network" on your console as if you were going to connect to a wireless Internet connection and choose "Windows Connect Now" instead of "Scan for Networks."
Turn on your computer and open Windows Media Player. You will need to properly configure the program to stream media. Windows Media Player 11 and 12 have different processes for media sharing.
Enable media sharing. With Windows Media Player 12, select the "Stream" drop-down menu and choose to enable media sharing. A dialogue window appears. Confirm the action. With Windows Media Player 11, click the small arrow below the "Library" tab and choose "Media Sharing." A new window appears. Click the box next to "Share my media." Make sure the Xbox 360 is selected in the window below and apply the changes.
Turn on the Xbox 360 and exit to the dashboard if neccessary. From the "My Xbox" menu scroll to either the music, video or photo blade and press "A." When prompted to choose your source, select "Computer."