I have a Sony VAIO desktop, purchased in 2006, running XP Professional with SP3, fully updated. I have the screensaver set to none, and the power settings set to turn off the picture on my monitor (ViewSonic) after 15 idle minutes. The hard drive is never turned off, the system never goes into standby, and the system never hibernates. This worked fine until a few weeks ago. Now I find my monitor always on, no matter how long the idle time has been. If I happen to be present at the end of a 15-minute interval, I can see the screen momentarily turn off and then turn on again, with no more than 2 seconds of darkness. I've tried updating my video card, monitor, keyboard and (wired, optical) mouse drivers. Nothing better than my present drivers was found. I've tried unplugging the mouse, and then the keyboard. This made no difference. I've found various forum discussions with Google on this and closely similar problems. None of them offered a solution (except one that would have required subscribing to see the responses to the question), apart from other users suggesting reviewing the power settings, updating drivers and looking in a very general sense for some software that might make the system believe it was not idle. Aside from Windows updates, the only software that might be recently changed would be my antivirus, ZoneAlarm Extreme Security, which from time to time updates itself. The only software I _know_ of, anyway. Does this remind anybody of possible causes or solutions? Thanks for any comments.