I have an XP (SP3) system. A couple of days ago Windows Update started taking 100% of the CPU just after system boot up. Windows Update appears never to finish or do anything. It is possible to work on the computer at the same time but it is very slow. You can hear the system ramp up when windows update starts.
I ran process explorer and was able to identify the process as windows update. I can kill it and the CPU usage immediately drops.
Any help would be appreciated.