Things You'll Need
Instructions
Turn on your Xbox 360. Ensure that you have no game disc loaded in the tray.
Navigate to "My Xbox" on the console menu and press "A." Go to "System Settings" and press "A" again.
Select "Memory" from the list options and press "A." In the Memory menu, highlight "Hard Drive" and press "Y."
Choose "Format" from the list of options, then press "A." When it asks you if you want to continue, select "Yes" by pressing "A."
Type in the console serial number on the next screen by highlighting each on-screen number and pressing "A." Once you have entered the number, click on "Done" to finalize the reformatting process.