do you have the latest firmware for your phone ? *#0000# plug it on the home screen to see what version you have. the latest for your phone i believe is v31. see ifyou can update via fota or NSU
here is what fota means, also i am not sure that your phone is supported for fota.
this is a link to nsu - nokia software updater
you can either do the first two. make sure you have a back up of your stuff using either nokia pc suite or ovi suite
or you can try taking the battery out for a moment and reinserting and seeing if this helps you any. it sounds like a bug
now read the below carefully, the first one will not make you lose any data the second one might. see if factory default restore might help and follow it with taking the batt out for a minute or so.
1. *#7780# - Restore factory settings - resets all the settings to the default ( you will not lose any data)
If these codes are not working the only thing for you to do is contact your Nokia Care Center/Service for assistance.