I recently installed Ansys 12.1 products on my computer. I think there is some kind of conflict between Ansys License Manager service and Norton service (ccSvcHst.exe). Since when the Ansys service is enabled, my CPU goes as high as 50-60 percent occasionally, for example when my computer is idle and there is no running program(the high CPU usage is caused by ccSvcHst). When I disable Ansys license manager service and restart my computer the problem vanishes.