Problem with Win7 Going to Screen Saver and Sleep Mode?

Starting a couple of days ago, Screen Saver and Sleep Mode are not starting as scheduled. I'm running Win 7 64bit and have had my setting established since I got the computer. There appears to be something running in the background that is preventing them from starting. As I watch the screen, I see something flash on the screen for a second, just a quick flash, not long enough to see what it is. The only thing I have running at startup is "Computer and Outlook 2013" which I have always had in Startup.

I looked at MSConfig and Services, but could not determine what this might be. Is there anyway to nail down what is causing the quick flash on the screen, as I think it is probably preventing Screen Saver and Sleep Mode from starting.

Thanks for any insights and tips on what to do.
Charlie

Uncheck everything in msconfig>Services and >Startup tabs (after Hiding all MS Services), reboot to see if problem persists.

Then add back your AV to see if it's involved, very possible if its bloatware like AVG or Avast instead of recommended MSE or Panda Cloud.

From there work through these Sleep Mode Problems - Vista Forums

There's no reason to use a Screen Saver which were to protect old CRT terminals. So I'd turn it off and use one of the Aero theme slideshows which are spectacular. You can even have the whole collection from 120 Original Windows 7 High Resolution Scenery Regional Wallpapers Free Download by downloading the folder then browsing to it from Control Panel>Personalization>Desktop Background.