Hard reset Nokia Lumia 521

1. From the Start screen, touch the screen and slide left.
2. Scroll down to and touch Settings.
3. Touch About.
4. Scroll down to and tap Reset Your Phone.
5. Read the prompt about your personal content being erased and if you agree, touch Yes.
6. Touch Yes again to confirm.

Nokia 521 hard reset

1. Back up any data stored on the internal memory of the handset.
2. Turn off the phone.
3. Then press the Power key to turn the phone on
4. Immediately press and hold the Volume Down button.
5. An exclamation mark (!) will appear on the display.
6. Press the following buttons in order (Note: nothing will change on the screen while entering the sequence of buttons):
   1. Press the Volume Up key
   2. Press the Volume Down key
   3. Press the Power key
   4. Press the Volume Down key
7. Your Nokia Lumia 521 will automatically reset.