Windows 7: Trouble connecting windows 7 , windows media center to xbox slim

I have been having trouble connecting mypc to my xobox slim. I have been through the network setting, all match up. the xbox can connect to live, it just won't connect to my pc. i allow all conection and turn off a/v and firewall still with no luck. i even tried connect them through ethernet wire, again no luck. i know my pc can connect to a xbox ( old white big guy) both wireless and wire, but i am having no luck with my xbox slim. and yes i have reset all extender stuff on pc and reet pc connection stuff through my xbox. the a/v i have is microsoft secrity esentals. any help will be gladly tried

What error do you get exactly? Have you googled the error code?