In order to hard reset a Nokia 8250, you should perform the following steps.
Remember! Hard reset will delete all the data on your device; pictures, contacts, messages, apps and more.
Nokia 8250 device will be brought back to the default configuration of a brand new device.
1. Press-hold the Power button until the phone turns on.
2. Press Call button and type in this code: 2945#*101# or 1809#*101#
3. Press Call again to confirm.
4. Wait for the phone to reset and restart.