how do i connect my xbox 360 to my computer to play music with media center help!!!!?

[Gigi Buffon Number 2]

first of all i have windows xp and a wired modem i installed media center and added my songs then i got the code thing on my xbox then i went on a site that tells u what to do and i says u go to media extender wihich i did on accesories and then media center the u click on media extender but its not there can someone help me so i can connect my 360 please!!!