You use your Xbox Live gamertag to identify yourself during games that you play live online from your Xbox game console. If you forget your gamertag, you can recover it through Xbox Live. Xbox Live requires an e-mail address to link to each gamertag, but if you forgot which e-mail address you started your Xbox Live account with, you can still recover your gamertag.
Visit the "Windows Live" website (see Resources).
Click "Sign Up" and create a "Windows Live" ID account by following the on-screen instructions.
Select "My Xbox" from your Xbox Live account on your Xbox.
Select the "Manage Account" option on your Xbox.
Select "Your Information" from the drop-down tab.
Select "Windows Live ID" and then select "Change Windows Live ID."
Enter your new Windows Live ID and the password you created for it. If you already had a Windows Live ID, select "Backspace" to delete it from the location that you'll type your new ID into.
Scroll down and choose "Yes, Change the Windows Live ID associated with your Xbox Live account."
Scroll down and choose "Update Contact Information." You will return to your Xbox Live's main dashboard menu.
Remove any discs from your Xbox console.
Select "Recover Gamertag from Xbox Live" from the dashboard.
Enter your new Windows Live ID and password and follow the on-screen instructions to retrieve your gamertag.