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.
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