press answer key ( green key ) + * + 3 + Power switch and wait untill the phone show Nokia on the LCd and blinks giving it again because phone will not show Formatting word on the LCD as in 6600 and 7610 and 6670

and this way can repair Contact Retailer too

tested..

*#7780# phone will ask you for Security code and I hope that you know it!!

Default is 12345


good luck