Nokia 100 hard resetYou can format your Nokia 100 device using the Restore factory settings option in menu:
Press left soft key (LSK) to enter Menu > Settings > Restore factory set. > Press select using LSK and Enter security code.
Default Nokia 100 security 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.
Formatting the device will permanently erase all user data and settings as well as add-on applications and operator specific settings.