You need the XBConnect programme to run on the PC:
http://www.xbconnect.com/
And you need to have an XBConnect-suitable network setup:
http://www.xbchelp.com/
The XBox needs to be on the same network as the PC. e.g. have both PC & XBox connected to a router & the router connected to your modem, or use ICS (Internet Connection Sharing) & have the XBox connected to the PC & the PC connected to the modem. There's lots of info on how to set it all up at
www.xbchelp.com
