I have only just started using this feature. I have my monitor set to turn off after 5 minutes.

After boot up this works ok for a while but fo no apparent reason stops. Going to Control Panel the setting is correct. I 'reset' and applying the 5 minutes again but it makes no difference. However, if I restart the PC it works OK until the next time, which may be a few hours or a day later.

Any suggestions please.

The only thing that comes to mind is that there may be something running that is preventing the power save mode. For example, if a video is playing, then the power saver settings will be over ridden and stay on. I'm sure it's nothing as obvious as a video playing, but there could be something else running that is over riding the power save mode. Keep an eye on the taskbar and task manger and see if there is something there that may be the culprit.

It's the only thing I can think of off the top of my head. Good Luck!

commented: My thoughts exacally +0

Opening Task Manager I found a program from my TomTom SatNav running. I don't know why because I haven't connected it for some weeks and TomTomHOME.exe has been removed from my start up entries. I'm not sure which it was but there are two contenders in the TomTom directory TomTomHOMERunner.exe and TomTomHOMEService.exe.
I cancelled the process in Taskmanager and the power saver worked. Goodness knows what it was doing as nothing showed on the screen and I don't know why it was running anyway. Neither of them are in my start up list but presumably was left over from when TomTomHOME.exe last ran. But having said that I have rebooted at least half a dozen times since I last ran it.

Anyway thanks for the suggestion.

PS Having just checked Date Last Accessed it would seem to be TomTomHOMERunner.exe that was the culprit

This is getting odd. If I set the timer to 1 minute the screen shuts down correctly. Same for 2 minutes.

It doesn't work for settings of 3 or 5 minutes.
Setting it back to 1 or 2 causes it to work ok.

No rebooting between changes and no changes to running programs. IE and firefox only on but not being used.

I think my last reply was a red herring.

Problem solved.

The time delay on my screen save was set to 3 minutes and was clashing with the time I was trying to set in my power options. It works fine now providing the value in the SS is greater than the PO.

This applies even if the SS is set to 'none'.