Of the four computers I installed Windows 8 Professional upgrade to, one of the computers will jump to 99-100% CPU use when idle for about a minute. Any activity by me (access menus or programs) results in the Service Host: Disk Defragmenter to stop and return to normal low CPU use. The PC has three hard drives, all of which report to be fully defragged (ought to be after days of defragging ;-) ).
I unplugged two of the hard drives to determine if one drive might be the culprit, but no change was observed.
The CPU temperature jumps from about 42 degrees Celcius to 49 degrees while the task manager is showing the defragmenter to be running, so I am assuming that the CPU graph in task manager is correctly showing CPU activity.
While the disk defragmenter is running there is 0% disk activity on the graph as well as the hard drive indicator light showing no activity.
The computer is also often very slow to boot, sometimes taking ten to fifteen minutes or longer (I do not use the computer very often so I thought that perhaps it was installing updates).
The computer is a home-grown Asus M3A motherboard, AMD Sempron LE-1300, and 4g RAM. Windows 8 was installed over the existing XP.
Before I attempt a reinstallation (eek! lots of programs!) I was hoping that someone might know of a quick fix. Thanks!