intermittent failure of screen saver and power settings.

intermittent failure of screen saver and power off to activate?

Hi.
My Win 7 Desktop computer, unlike my laptop and other Win 7 computers, has a power and screen saver setup that, at times, never activates? I have checked background processes and can't understand why at times it kicks in and other times I must reboot to get it to kick in. It always works after a reboot as long as I do not use the computer. Sometimes when I use it, the screen saver and power setup will go on, sometimes not?

My screen saver is not a 3rd party one and the same for the power settings. They are the ones that part of the Win 7 pro Os.

Has anyone ever heard of this? What do you suggest? Any help is greatly appreciated!
Thank you very much for any possible solutions.
sincerely,

Miles

P.S. I have done a SFC /scannow and no problems were found. I also checked my Lan Driver Properties to make sure the box was unchecked for waking up the computer.

P.S.S. My Computer is a Win 7 Pro with an i5 3rd generation Intel 3.20 GHZ CPU with 16 GB of DDR3 Ram and a 1TB SSD HD.

P.S.S.S. All Drivers Have Been Updated.

Would someone please read my above post, and if possible, offer me some advice regarding my screensaver, etc.?

Thank you very much.

Sincerely,

Miles

Thanks for your reply.
Yes, I have run SFC /SCANNOW AS ADMINISTRATOR several times without error.
I did a system restore to a date when I thought there was no problem? This too did not correct the issue.
I disabled certain shell extensions that were not related to the OS and that too failed to correct this issue. I also unplugged and changed mice to different USB ports with no help.
I did notice on one report that " USB DeVICES did not enter the Susped State."
However, on other computers at my home running the same OS they have the same "Suspend State", yet they do not have this intermittent failure of the ScreenSaver and Power settings to activate according to my settings!
Once again, this only happens after I begin using the computer. If I do a simple restart, and not use the computer, the screensaver and power settings always activate. If I begin using the computer, sometimes they activate and other times they do not?
I have the screensaver set for 1 minute so I can tell if there is activation.
My one solution that works is to restart the computer when done using and the screen saver and Power Settings always activate.

It seems like one of the post boot programs I use maybe interfering with these settings but I can't find which, if any?
Thanks for any further guidance

Miles