Reset Window Phone 8 in Lumina 520

Some your phone have error with Limina 520. You can reset your phone.
1. Backup all your data to the internal memory.
2. Turn off the phone
3. Turn press Power key to turn on phone.
4. Immediately press and hold the Volume Down key. An exclaimation mark ("!") will appear on the display
5. Press the Volume Up key.
6. Press the Volume Down key.
7. Press the Power key.
8. Press the Volume Down key.
9. The phone will automatically reset.

• During the reset, there will be two gears rotating on the display for up to 5 minutes, after which the display will go blank for about 30 seconds.
• Resetting the phone will erase all user data, including Nokia Maps. You will have to reinstall the Nokia Maps via Wi-Fi.
• To restore your phones settings, email accounts and apps, instruct the customer to use the “restore your phone” option during the start-up sequence.

Good luck to you.