you may need to reinstall the operating system. This will wipe the phone and take about half an hour. Att can wall you through it and send you the latest operating system they support. tis is what I did to fix mine.
On a PC, Go to: Windows 32 Bit Crogram FilesCommon FilesResearch In MotionAppLoaderLoader.exe Windows 64 bit: Crogram Files (x86)Common FilesResearch In MotionAppLoaderLoader.exe
If you you are unable to find this file, you will have to perform a search through your Windows computer for this file name. You may also go to the file by clicking on Start > Run. In the run command, copy and paste the file path above and it should bring you directly to that file in Windows.
The Application loader will open. On the Welcome screen, press next. At the Port Selection screen connect the BlackBerry without a battery. Press next once the PIN shows up, or Unknown shows in box. Put in the battery if no PIN shows up. At the device Application Selection screen, select all modules to be reloaded onto the device then press Next. Most 3rd party applications can be selected and would be kept on the device. Press the Advanced button. On the Device Data Preservation screen, make sure both boxes are checked to delete all application data, and all currently installed applications. They may be grayed out and already selected or you may have to check them manually. Press Next. Once you select to erase all data, the Loader Wizard may ask to make a backup. Select Do not automatically backup and restore device. Please ensure the battery is inserted properly in the phone and press next. While the device is being erased and reloaded. Please wait for the process to finish and DO NOT unplug the BlackBerry or turn off the computer. Test the device for 24 hours and perform a selective restore on the device using the Desktop Software.