- Switch off your device.
- Now remove your SIM Card and Memory Card.
- Now press and hold these three keys
- Now without leaving these three buttons press another
- Now formatting process will start on your device.
- Now just wait for formatting to be finished.
- Now your formatting will be completed and you can start installing your stuff back.
So now your phone will be freshed up and can be used again in normal manner, this works basically for every nokia device but if you think its not working do comment so that I can check out the matter and help you out.