Instructions
Turn on your XBox 360 and a controller.
Select “My XBox.”
Choose “System Settings.”
Select “Memory.”
Scroll to “Hard Drive” and press the “Y” button on your controller.
Select “Format” and confirm that you want to reformat the drive by choosing “Yes” when you receive the confirmation message.
Enter your serial number if you are asked for it. The serial number is located on the back of the system.