Way to Full Format Nokia 7710 (HARD RESET!!!)

-Disconnect the charger and remove battery.

-Wait for about ten seconds and inseert the battery to start the device.

-When you see the NOKIA welcome screen, immediatley press and hold two keys on the left side (the [= key and the Menu key) and shortly after that press and hold the second key from the top on the right side on the phone.

-Confirm that you want to format. Formatting will start.

Enjoy..