How do I reset my Nokia Lumia if it does not work properly? - Nokia FAQ
If your phone is unresponsive, or it gets stuck showing Nokia logo, then try this: Press and hold both the Volume down and the Power keys for 15 seconds. This should get your phone to restart properly again. If this does not help, then follow next steps to perform OS reset.
Warning: Resetting your phone will return it to the same state it was in the first time you turned it on. All your personal content in the phone, including text messages and apps that you been purchased and downloaded (may be re-downloaded again) will be erased, and the phone will be restore to the factory settings.
Here are two options to follow, depending on whether you can access your phone's settings screen or not.
Option 1: About menu
- Use this option if you can access your phone's settings.
- This option warns about data loss.
On the Start screen, swipe left, select Settings > About > Reset your phone.
Option 2: Hardware key combination
- Use this option if you forget or lose the password.
- Use this option if the phone fails to fully switch on when pressing the power on key.
- Note: No warning about data loss!
Nokia Lumia with Windows Phone 8
Step 1
Make sure the charger is disconnected.
1. Switch the power Off.
2. Press and hold the Volume down and connect the charger, if succeed an exclamation mark (!) is shown on the screen.
Step 2
Then input the keys in the following order:
1. Volume up
2. Volume down
3. Power
4. Volume down
Step 3
The phone will reset and boot up automatically. Please note that this may take several minutes.
Nokia Lumia with Windows Phone 7
Make sure the charger is disconnected.
1. Switch the power Off.
2. Press and hold the Volume down and Camera keys.
3. Press and hold the Power key.
4. When the phone vibrates, release the power key, but continue holding the volume down and camera keys, until the phone reboots.