Things You'll Need
Instructions
Turn on your Xbox console without a game inserted.
Navigate to the "Memory" section of the Xbox user interface and select "Hard Drive."
Search the list of hard drive content for any files containing the words "Xbox LIVE." When you find such content, select it with the "B" button and choose "Delete." Repeat this procedure until you have deleted all content you do not want to keep on your Xbox.
Call Xbox LIVE Customer Support. The number for this department in North America is "1-800-4MY-XBOX," or "1-800-469-9269."
When you reach a representative, explain to them that you wish to delete your Xbox LIVE account. Their contract requires them to try to keep your business, but if you explain to them that you are no longer using the account and do not want it accessed by third parties, they will cancel the account.