I used to always use Media Center on my X360, but I had a virus so I had to completely reinstall Windows 7 Ultimate. After getting my drivers reinstalled, I decided to get my X360 and Media Center back together. I opened up MC and my Xbox, the PC detected my Xbox and added it as an extender, all I needed was the 8 Digit number. One problem, even though my Media Center detected my Xbox, my Xbox can't find my Media Center! I tried formatting my Xbox Hard drive, clearing the Cache, I tried making my Xbox "forget" my network and re-establishing it, no go either. Disabling my firewall didn't do the trick either. I can stream my music and videos using Windows Media Player, but I want to use the media center. My host PC is a netbook so I can't use that as an entertainment center, plus, it worked like a charm on the Xbox on my big screen so... yeah... My PC Screen My X360's Screen EDIT: SOLVED! If you had the same issue as me, do this, disable your firewall, then on your Xbox, go to System Settings>Computers>Windows Media Center>Setup, you will get your key there, and it'll set up just fine!