Instructions
Remove all storage devices from your XBox, including flash drives and memory cards.
Select "My XBox" from the XBox main menu. Navigate to "System Settings." Select "Console Settings." This will open a menu listing of all settings categories on your XBox.
Select "System Info." Enter the following combination on your controller to open the "Reset System Settings" page:
Left Trigger > Right Trigger > X > Y > Left Bumper > Right Bumper > Up > Left Bumper > Left Bumper > X
Select "Yes, Reset Settings." Your console will now reinstall the original firmware. This process may take several minutes. Once the original firmware has been restored, you will need to reset all your custom user options.