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A hard reset will fix this issue straight away.
Make sure you make a back up with Nokia Suite first and don't tick the Settings box as this will backup the bug that's causing this. Once you've made the backup, enter *#7370# into your phone and default security code 12345, unless you've changed this code yourself.
Once the phone has rebooted, reconnect it to Nokia Suite and update or reinstall the current software to make sure you really get rid of all possible bugs. You can do this by clicking on the green arrow in Nokia Suite.
After you've done the above, place the backup back onto your phone and then it should work perfectly.
Let me know how you get on!