Restore original settings
Press Menu, and select Tools > Settings > General > Factory settings.
You can reset some of the settings to their original values. To do this, you need the lock code. 12345
After resetting, the device may take a longer time to power on. Documents and files are unaffected.
You can format your Nokia N85 device by typing: * + 3 + call + Power on. Before the device is reset, you need to provide the lock code. The default lock code is 12345.
If it is not working try this code:
You can format your device by typing *#7370# in standby mode. Before the device is reset, you need to provide the lock code. The default lock code is 12345.
Some Nokia phone can be reset via this menu option
Press menu button or enter Menu > Settings > Phone > Phone management > Factory settings > Delete data and restore > YES
Formatting the device will permanently erase all user data and settings as well as add-on applications and operator specific settings.