This trick is for almost all nokia models....(but may not work for S40 editions)
Before format your mobile backup your contacts.....
1.Switch off ur phone...
2.Remove sim card & memory chip...now phone is in switch off stage...
3.Now press & hold keys - 3, * (star button), call lifting button (green) ...
4.Then without leaving these three buttons press power button...
5.Formatting task will be started...
6.Remember its a very rare trick....
