Screen savers and turn off monitor function are not working, help!

[Pleinair]

Hello,

I have a problem on my Windows XP Professional SP3 desktop system.
The monitor never goes into screen saver mode on its own, and doesn't turn off as I scheduled it to do on the Display properties and Power schemes.

I tried many different things: changing the scheduled times for the screen saver and the Turn off feature, using different power schemes and screen savers (or even no screen saver at all), Unplugging my wired Razor USB mouse, ending different kinds of known expendable windows processes in the task manager.

I know the problem isn't with the monitor itself because:
A. I just changed into a different monitor recently and it was the same problem with my previous one (while the new one was turning off just okay with its previous XP desktop computer).
And B. The Screen Savers are working when I click the preview button in the Display Properties window.

I have this problem for several months now. At first only the screen servers didn't work but now it won't turn itself off either.
It really is an annoying problem because the only way I have to turn the monitor off now is either by turning off the computer itself or unplugging the monitor from the electricity (which just wouldn't do).

One more thing, I've just recently (a few weeks ago) replaced my old Dual core AMD system with a new Mobo, a Pentium Dual processor and new RAM + DVD RW drive.
I'm not sure if this has anything to do with the monitor not shutting down/going to screen saver mode seeing as I still use the same Hard-drive, operating system and Radeon video card as I used to before the upgrade.
Furthermore, I was experiencing the screen saver part of the problem even before I upgraded my system.

Can anyone please help me solve this problem which I'm confronted with?
Thank you for your time!

 

[MC_K7]

Did you reformat and reinstall Windows (clean install)? Is your BIOS updated to latest version? Graphics drivers updated as well? Might be some corruption in Windows, might as well reformat and reinstall.

In any case, it might be a good opportunity for you to upgrade to Windows 7 or 8. Did you know that Microsoft is going to drop support for XP soon? On April 1st 2014 they will stop releasing security patches for the OS so your computer will be at risk after this date. I would recommend you think about switching to a new OS soon. And reformatting and reinstalling to a new OS like Win 7 will most likely solve your screen saver problem at the same time.

Sorry but in my eyes it's just not worth putting effort on troubleshooting XP anymore as it will soon be abandoned by Microsoft and not supported anymore.