Instructions
Turn off the Xbox. Connect one end of the Ethernet cable into the "Ethernet" port on the back of the Xbox 360. Connect the opposite end of the Ethernet cable to the Ethernet/Internet port on your broadband modem or router.
Turn on the Xbox. Select the "My Xbox" tab. Select "Settings." Select "Network Settings."
Select "Test Xbox Live Connection." After the test is complete and the connection is successful, you can sign in to a pre-existing Xbox Live account or create a new one from the My Xbox tab.