Becuase i want to listen to the music on my Computer but my xbox says i have to register my console on my Computer?

Step 1: Get networking
To stream movies from your PC to Xbox 360 they’ll both need to be connected to the same network. To do that, you’ll need a router. It’ll also need to be near your Xbox 360 so you can connect it using the included Ethernet cable. If that’s not possible, you’ll need to buy a wireless adapter for Microsoft’s console in order to get hooked up.
Your PC will also need to connect to the network, so if it doesn’t have a network card or built in wireless, you’ll want to grab an add-on to get it connected.

Step 2: Run Media Player
To share videos with your Xbox 360 you’ll need to be running Windows Media Player 11. If you don’t already have it, run Windows Update from the tart menu, and rest easy for a minute as it installs.
Once it’s downloaded and ready for action, power-up your Xbox 360. Then start your PC running Windows Media Player. Right, now click “Library�and “Media Sharing� Next select “Share my media�and choose “OK� Wait for your PC to detect the Xbox, then select it and click “Allow�and “OK�
On your console, select the media menu, then choose Video, Music or Pictures. There you’ll see the same content from your PC. If it doesn’t show up, hit the “X�button on your controller, and select your PC. Now you’re good to go and start streaming movies.

If your connect them both the your home network, a wizard will prompt you through it.