How Do I Unregister My Mac?

Click the 'Apple' icon in the upper-left corner of the desktop and click 'System Preferences.'
Click 'MobileMe' in the Internet & Wireless section and click the Sync tab. Click 'Advanced' in the bottom-right corner of the MobileMe window.
Click the name of your computer in the account synchronization window and click 'Unregister' to remove the computer from MobileMe's registration.
Click 'Done' and close the MobileMe window to apply and save the new settings.
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