First check to insure your charger cord is not ruined. Many times this can be the main reason why your phone isn't charging. Try using a friend's cord or an additional one that you may have laying around. If this still doesn't work you will probably have to replace your battery. That is an easy fix! Hopefully that works, but if not your logic board must be replaced.
One option is to reboot your phone to its factory settings. To do this, follow the instructions below: 1. Home screen-> Open the All tray-> Select settings->Security-> Security Wipe 2. The security wipe options screen will be shown. (Select all options that are available to be deleted) 3. Enter "blackberry" in the blank box 4. Select Wipe data. Then the phone will reboot when complete. If this doesn't work you will have to replace the cursor button.