MobileBurn Forums - 7610 lock code: "Series 60

On a Series 60 v1 based phone (N-Gage, 3650, 7650), 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)

Deep 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.

On newer Series 60 phones (6600/6620/7610), the sequence is slightly different:
power the phone off,
press and keep down (simultaneously) the keys green/talk + ’3’ + ’*’, - power on the phone.
release the keys when the formatting starts."