In our description database there are 2 solutions for performing hard reset for Nokia Lumia 800.
Choose the first method and follow the steps to perform a hard reset. If the first solution does not work, try the next method.
Please remember! Hard reset will delete any and all data your device contains; like pictures, contacts, messages, apps etc. Everything. Nokia Lumia 800 device will be brought back to the same configuration as that of a brand new device.
1. Power up the device.
2. Select Settings...
3. ... About...
4. ... and Reset your phone.
5. Voila, done.