Windows 7 Automatically Logs Me Out

I am having trouble with my notebook. I recently decided to turn on the screensaver to "blank" after 10 minutes and set the power managemet to never turn off the display under either power condition. I would leave my computer for 10 minutes or so and then when I would come back, I was logged out. Yes, I mean logged out as in all open, running applications were closed, not just at the login screen. I searched the web and found many others with a similar problem. Most replies refer to the check box on the screensaver setup page that says "on resume, display logon screen." This is quite different though as even with that checked, the current user is not actually logged off and the running applications are not shutdown. I (and others with this problem) are actually being logged off. Incidentally, the box is not checked, and now the screensaver is diabled. Power management is set to never turn anything off, ever. I still have the problem. I then saw a post that said I needed to uncheck the "require password to logon" option in the user settings. Seemed odd since my computer worked as it should for the last 9 months with that option checked (by default), but I gave it a try. The system still logs me out. I then went back to the screensaver and re-enabled it with the "bubbles" but this time, I set the timeout to 9999 minutes, figuring that it would then take a week of idle time before it logged me out, if in fact that was the problem. Didn't work, still being logged out with applications running. I have searched all over the web, but can't find a solution.