Lo único que se me ocurre es resetear tu N-Gage:
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.