In order to hard reset a Nokia 7373, you should perform the following steps.
Remember! Hard reset will delete all the data on your device; pictures, contacts, messages, apps and more.
Nokia 7373 device will be brought back to the default configuration of a brand new device.
1. Use Power button to turn on the phone.
2. Now open Menu (press Center button) and select Settings and Restore Factory Settings.
3. Now select All.
4. You will be asked for the security code. Provide it. Default code is 12345.
4. Your phone will reset & restart. Well done!