I had a single 1920x1080 monitor on a Windows 7 desktop PC and, per "power management" (not screen saver), the screen would go blank after 10 minutes.

I added another monitor (2560x1600 if that matters) and since then, neither screen has ever blanked. I've tried turning on the "blank" screen saver, but that didn't help either -- I can go away for hours and when I come back, both screens are on.

I've seen others with similar issues apparently caused by e.g. wireless mice that seem to move infinitesimally, but I've got the same wired mouse I had before. I can't understand why neither the screen saver nor power management is doing what it should to blank the screens, when "power management" used to do it when there was only one monitor.

Maybe it doesn't matter so much with current LCD display technology (no "burn in") but doesn't a monitor use more power when "power management" hasn't turned off the display?

Thanks for any suggestions.