Try the following resolutions in the order in which they are listed:
1. Turn off your Xbox 360 console, disconnect and reconnect all cables, and then again turn on your console. If this step doesn't resolve the problem, try step 2.
2. Turn off the console, and then disconnect any connected accessories, such as controllers, Xbox 360 Memory Units, and the Xbox 360 Hard Disk. With these accessories removed, restart the console to see whether the problem persists and to pinpoint whether the problem involves the console or an accessory. If this step doesn't resolve the problem, try step 3.
3. If you continue to experience the problem, contact Xbox Customer Service.