How To hard reset Nokia 5230

Restore the 5230 original factory settings

Restore original settings
Select Menu > Settings and Phone > Phone mgmt. >
Factory settings.
You can reset some of the settings to their original values. To
do this, you need the lock code.
After resetting, the device may take a longer time to power
on. Documents and files are unaffected.

Nokia 5230 hard reset with buttons / keys

Press and hold GREEN + RED + CAMERA when powering up, then
input default 12345 security code.

or
Enter     *#7370#  

Reset the Nokia 5230 device

1. Switch off the device. 2. Remove the battery. 3. After a few seconds, re-insert the battery, and switch on the device.