OK, next step.....reload the OS using BlackBerry Desktop Software. If that doesn't do the trick, it's time to get another phone.
Cheers. 
- If my response has helped you, please click "Options" beside my post and mark it as solved. Clicking the "thumbs up" icon near the bottom of my response would also be appreciated.
My Z10 was furnished by BlackBerry but all opinions are my own.
