I use the Stardock Start8 start menu, and from there I sometimes select the Sleep option. When I do for the 1st time in a session, all that happens is the video signal to the monitor is turned off. The screen goes black, and the computer continues running as normal. And as soon as I move the mouse, the screen come back on. That is not a proper "sleep" as I understand it.

However, if I select Sleep again from the start menu during the same session, it then not only turns off the signal to the monitor, but shuts down the power to the computer except for the RAM, and the power button blinks. In other words, it goes into a true sleep mode as I understand it.

So my question is: why does my machine not go to sleep on the first attempt? I can reproduce this same behavior in each new user session [i.e. after each reboot]. My computer obviously can go to sleep, but why not on the 1st request to do so? This does not seem like a "feature" to me, so I'm guessing something is off in my configuration.

I have an up-to-date and other fully functional install of Windows 8.1 Pro x64 as far as I know.

I'd greatly appreciate any help in figuring this out. Thanks!