Chosen Solution

lumia 520 is not reseting ,and gets restart after opening any file

Nokia Lumia 520 hard reset: if you use windows 8 Turn off your phone. Press and hold the Volume down and connect the chargeryou will see exclamation mark (!)Press below keys exact order

  1. vol up
  2. Vol down
  3. Power
  4. Vol down phone will be reset will all content except SD card If you use windows 7 Turn off your phonePress and hold volume down and camera keypress and hold the power keyyou will feel an vibrate so you can release only power key and keep pressing vol+ cam key until phone reboots phone will be reset will all content except SD card