How to format your nokia series 60
It may happens that a program corrupts the C: drive of your phone. In such case, some data can be lost of course but, more annoying, some applications may not work or work only partially...

On a Series 60 based phone, two key sequences will allow to restore your phone to a cleaner state:

Normal Reset *#7780# : Restores ini files from rom but preserves user data (photos, 3rd party apps etc)
Hard Reset *#7370# : This reformats completely the C: drive. All applications and files stored on this drive will be lost and clean default files will be rewritten.

In both case, the phone will ask you a confirmation and you will have to enter a security code (12345 by default).

Files and applications stored on E: drive are not be affected by these sequences.

Note : Full phone formatting a 6600!
Here to let everybody how to perform a Full phone formatting on a 6600!
If you encounter situation like below on your 6600 :
1. Blank screen phone unable to reboot.
2. Phone only able to boot-up to "Nokia" word screen.
3. Install some program but not able to uninstall it after that.
4. Unable to delete unwanted files on C drive.

Do a Full phone formatting on your 6600! as steps below :
1. Make sure you have at least 3/4 charge of battery power left.
2. Backup your contacts list and personal files to MMC memory card.
3. Switch-off your 6600 phone and REMOVE UR MMC!.
4. Press and hold 3 keys : Green dial key, * Star key, no. 3 key on keypad and then press the power on/off to swtich on the 6600 phone. Remember, do not let go the 3 press and hold keys until you see a formatting word screen show!
5. After a few minutes when the Full phone formatting completed, your 6600 will back to original system and factory settting

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Series 60 Handset Information