Connecting to a Wireless Network
To connect to a wireless network for the first time, select "System Settings" from the Xbox 360 dashboard. Choose "Network Settings" and pick "Configure Network." In the "Basic Settings" section, choose "Wireless Mode." Choose "Scan for Networks" and select your home or office's network, then enter the password or WEP key if necessary. If your network isn't listed, choose "Specify Unlisted Network" and enter the name of your network manually. Choose "Done" and pick "Test Xbox Live Connection" to finish setting up your wireless connection.
Updating System Software
The black Wireless N version of the Xbox 360 Wireless Adapter requires that the Xbox's software be updated before the adapter can be used. With the adapter unplugged from your Xbox 360 and no Ethernet or network cables attached, insert the setup disc bundled with the adapter into the console. Turn the console off and on again and select "Yes, update now." Wait for the "Update complete" message, then connect the Wireless N adapter. Remove the disc from the drive and turn the console off and on again, then proceed to the "System Settings" menu to set up the connection.
Improving Signal Strength
If your wireless signal is weak, your Xbox 360 may fail the initial Xbox Live connection test or cut out during online play. To improve signal strength, make sure your Xbox 360 is as close as possible to the wireless modem or router you use to connect to the Internet. Most modems or routers will not give a strong enough signal for online play if the console is more than 30 feet from the device. Check that there are not too many walls or solid objects between the router and console. Ensure there are no wireless devices that could interfere with the signal strength, such cordless phones or baby monitors, placed between the console and router.