Did you try doing System Restore? If no and if this issue started occurring after doing some recent software changes on your computer, then I would suggest try restoring your system back to a date when it was working fine. System Restore will affect Windows system files, programs, and registry settings only.
For System Restore steps, you can refer to the URL mentioned: http://windows.microsoft.com/en-US/...
Kindly revert and let us know the status.
Thanks & Regards