If you encounter any problem with your phone and can't find a fix for it, check if you have the latest firmware first - you might need an update. If problem persist do these following steps until it's fixed:
- Perform a soft reset - *#7780#.
- Do hard reset -*#7370#. Make a back up from PC Suite as this will delete everything (excluding your memory card/mass storage).
- Reinstall your firmware.
- If everything fails, you need to call Nokia or visit your nearest Nokia Service Center for repair or replacement.