I've been having a problem that I can't seem to solve. I hooked up my Xbox 360 to my HDTV to use as an extender. When I hook it up hardwired to my AT&T DSL modem it works great. I decided to go wireless with the official Xbox adaptor because I didn't feel like picking up 50 feet of cable every day. Anyway.... I hooked the adaptor up and it connected to live right away. I could also stream my playon software and watch Hulu, Youtube,ESPN and so on. It works flawlessly. So I click on the Media Center option and it found it and connected. After that the screen went black. Media Center would not come up at all. I tested the conection over and over. I deleted and readded the extender over and over and it does the same thing.

 I went back to my computer and opened media center and used the tuning element. When I did that it said not enough bandwith and it showed a real low level on the chart that came up. I don't see how that can be right. My playon server streams with no problems at.  Hulu plays real quick and doesn't freeze at all. Xbox live works perfect and I never have any lag on it at all. So I'm really confused about why media center goes to the black screen. I really wanted to use it as a DVR and I really don't want to use it hard wired.

 I have a Dell studio slim with a quad processor and 8 gigs of ram in it. My broadband is through AT&T DSL and it's the elite that runs 6mbps I think. The AT&T moden is a wireless gateway that runs on the G band. I do have Noron Internet Security 2010. I disabled that and it still went to the black screen. If anyone can help I would appreciate it. Oh yea I'm running Vista home premium 64 bit. Thanks guys I appreciate the help.

Disabling Norton (or most any other AV/security suite) doesn't really disable it (especially the firewall component.)  Uninstall Norton, and then run the Norton Removal Tool (just Google that.)  Reboot as directed.
Once that's done, check it again.  If it works, the fault lies with Norton (or with its config.)  If it doesn't, the fault lies with the network connection. 

MC Extenders do require a fairly robust network connection.  The fact that the network tuner says "not enough bandwidth" says that the fault likely lies with the network connection.  Can you try (just as a test) hardwiring the 360 to your network, and seeing how well it works?