Do you use the Portable or Installed version? What version is currently installed?
Try re-downloading from their website, and perform an over-the-top installation or repair.
Is there any security software that could be conflicting?
Check the Windows Reliability Monitor in the Control Panel.
Code:
Control Panel\All Control Panel Items\Action Center\Reliability Monitor
I agree. Re-downloading & installing is terrific advice. Approaching Privazer as though you've never used it before (like me!) is a good way to ensure you'll be able to have it's latest updated version!