How to format Nokia symbian S60 phone

There are two type of format, soft format and hard format.
Soft format means restore all default setting from the factory, hard format will remove all data on your SD/MMC card.
Here are the steps to soft format your nokia symbian s60 phone:
1) Backup your contacts list and personal data to SDcard with Nokia PC suite.
2) Type *#7370# and *#7780#, which will prompt you restart your phone.
3) The format will take almost 3 minutes, after formating and restart the phone, restore your data with PC suite.

Here is the hard format steps:
1) switch off your phone with power off.
2) Please press the three keys together
   - Dial key
   - Sharp key (#)
   - One key (1)
or there are another three keys:
  - Dial key
  - start key (*)
  - No three key (3)
2) And swith on your phone, don't let go three press, and wait for the prompt of formating.
3) Wait some minutes to complete the formating.