Instructions
Go to the Xbox sign-in page (see Resources).
Click the "Forgot your password?" link below the sign-in area.
Enter your email address and the verification characters provided for you and click "Continue."
Choose from either "Send yourself a password reset e-mail message" or " Provide account information and answer your secret question." Choose the first option, and after answering the secret question, Xbox will email you a new password. Choose the second option, and after answering the secret question, Xbox will tell you your password.