I've had my Xbox 360 since June. Love it! Now I am ready to start my Silver membership on Xbox Live. Anywho, I have Comcast broadband internet and the modem I have is a Motorola SB5100 Surfboard Cable Modem. I connected the ethernet cable from the 360 into the back of the modem (which was plugged in and the cable wire was connected). And I did the connection test and it couldn't find an IP address. Any one know what to do?