updating in win 8.1 throws critical process died

i was using win 8 .1 RTM and after somedays of installation it asks for restart for update but when ever i do it says critical process died 1. i tried reseting it becomes ok but again after few days it asks for update and same issue 2. i tried clean install of win 8.1 by formatting clean hard drive but still when ever it restarts after updates it says critical process died