There are times when all electronic devices fail to perform properly. Nokia designed its 7390 mobile phone to restore itself in the event that the device fails to operate. To perform a hard reset on the phone, you must restore the device back to its factory settings. All menu options, graphics, ring tones and other customisable features on the phone are removed and overwritten by the default settings. The only exception is the phone's stored contacts; these will remain intact.
Turn on the Nokia 7390 phone and select the "Menu" key.
Choose the "Settings" option from the main menu.
Select "Rest. Factory Sett.," which stands for "Reset Factory Settings," in the Settings menu.
Enter the Nokia 7390's security code when prompted. The default security code is "12345." The phone will now reset and recover itself to factory settings.