My full system scan hangs about once every two weeks. Today it stopped at about 70%, but yet said it was still scanning for several hours. Could not stop, pause or turn off even in the task bar. Had to reboot. Next scan finished early and way too fast. Norton Power Eraser revealed: Registry System Settings Bad. Fix/removal failed. 2nd time it reported it in the last two weeks. Restart does not help. 12 successful full system scans in the past two weeks.