In order to hard reset a Nokia 8850, you should perform the following steps.
Remember! Hard reset will delete all the data on your device; pictures, contacts, messages, apps and more.
Nokia 8850 device will be brought back to the default configuration of a brand new device.
1. Power up the device.
2. Press the Call button and type in this code - 1809#*101# or 2945#*101#
3. Press Call button again to confirm the process
4. Voila! The phone will now reset and restart.