Formatting a Nokia N70 phone

Here’s how to hard reset or format your Nokia N70 mobile phone:
1) Switch off your phone
2) Press and hold these 3 keys together:-green dial key-the star key(*)-the number 3 key (Ugh, I wish I had three hands…!!)
3) Power on the phone

Warning: Do not release the keys until you see a formatting screen and even after the phone has started. Wait until the initial sound starts to play and the hand animation is displayed.

Source(s):
http://thinkabdul.com/2006/07/15/formatting-a-nokia-n70-phone/