Contact your operator immediately:
Note: Nokia customer support doesn't have the possibility to block the SIM card or the device, or track a stolen device.
To minimize the risks caused by the theft or loss of the device, there are some security features which you can enable in your device:
Note that the phone autolocking and remote locking cannot be enabled after the device has been lost, so it is important that you enable these security features already when taking the device in use.
These simple steps can help in a majority of cases.
Restart your phone
For phones with removable battery:
1. Switch your phone off
2. Remove the battery.
3. After a few seconds, put the battery in and switch your phone on.
For phones with non-removable battery:
1. Press and hold the power button until the phone vibrates and switches off.
2. Switch your phone on again.
Reset the settings
Restore the original factory settings as instructed in your phone's user guide.
Update the software
Make sure your phone is running the latest software. For downloads and assistance, go to your local Nokia website's support page.
Select Menu > Settings > Rest. factory sett. (or Reset device or Restore factory sett. or Rest. fact. sett.).
Enter the security code before the restore. If you have never changed your security code, then enter the default code 12345. If your phone still requests a security code or if you have forgotten it, please bring it to the nearest Nokia Care point for inspection.
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
On the Start screen, swipe left, select Settings > About > Reset your phone.
Option 2: Hardware key combination
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.