Keeps on ticking

I’m running PSCS on a Win XP machine (lots of horsepower). I thought I had a problem with my screensaver, not starting at all. But tonight I left PS on the screen and went away for about half an hour. When I returned the screensaver had not started (set for 5 mins.). I checked the Task Manager and found that the PS process ticks over continuously using 6 to 10 percent CPU even when nothing is going on, not even an image opened. This is enough activity to prevent the screensaver from starting.

Has anyone else experienced this? Is there a workaround?

Thanks, MCG