Instructions
Installation
Turn on your Xbox 360 console and insert the installation disc that came with the Xbox 360 USB wireless adapter. Disconnect the Ethernet cable from your Xbox 360 if you have one plugged in.
Turn off your console, and then turn it back on. If a message that says "Mixed Media Error" pops up, turn on the Auto-Play feature and restart your console again. To turn the Auto-Play feature on, select "Settings | System | Console Settings | Auto-Play | Enable."
Select "Yes, Update Now" when prompted. Once complete, remove the installation disc from your Xbox 360 console, and then turn it off and on one more time.
Connect to a Wireless Network
Select "Settings" from the main menu, choose "System Settings," and then select "Network Settings."
Press the "X" button to scan for wireless networks in range, and then type in your network password.
Select "Text Xbox LIVE Connection" to test your wireless connection; select "Yes" if you're prompted to install any console updates.