04-07-2013 05:28 PM - edited 04-07-2013 05:29 PM
Start with a battery pull. Remove your battery while your phone is powered on then replace it.
If that doesn't do the trick, try reloading your OS. To do this, plug your phone in to your PC and open BlackBerry Desktop Software. Click Device at the top of the software then Restore. Choose the most recent restore point and load it.
Try those suggestions and post back with your results.
EDIT: If your phone is not being recognized by BlackBerry Desktop Software when you plug it in, have a look at this article:
www.blackberry.com/btsc/KB10144 . Cheers.