Instructions
Turn your Xbox on. Select "System Settings," and then "Console Settings." Select "System Info." Write down the serial number given for your Xbox 360 console.
Sign into your Xbox account on the Xbox homepage (see References for link). Click the "Support" button.
Select "Hardware" as the "Support Category." Click "Repair your console" under "Console Management." Select "Register a new console." Enter your Xbox 360 serial number and click "Submit." Choose "Request a repair" for that console.
Select the reason for the repair, such as: "console not responding," "flashing red lights," "video issues," or "audio issues." Describe the problem in the provided text box.
Confirm your shipping address, which is based on the information on your Windows Live ID. Click "Submit."
Write down the 10-digit service request number given to you on the receipt screen. The service request number is also emailed to you.