How To Reset - Nokia Lumia 720
Learn how to reset your phone on Nokia Lumia 720. This restores the factory settings, and erases all your personal content, including apps you've purchased and downloaded.
On the start screen, swipe left, and tap Settings icon > about > reset your phone.
If your issue remains unsolved, contact your network service provider or Nokia for repair options. Before sending your phone for repair, always back up your data, as all personal data in your phone may be deleted.
Note: If you need to identify your phone, to view the unique IMEI number of the phone, dial *#06#.