This is an update to my original posting.

I installed a Sleep-keyboard Macro (Rundll32.exe Powrprof.dll,SetSuspendState Sleep), and it works fine.

Now for the peculiar part (meaning I don't...

Just to follow up. Nothing has worked so far, including setting to defaults, uninstalling the last W10 up date, setting and resetting the C-state, etc. so I set up a Macro, and will use that.
...

Uninstalled latest W10 update, with no effect on Sleep Problem.
Have reinstalled update, and set C-State to "Enabled" vs Auto. Will see if that makes any difference.

I have a small OC using the ASUS M/B auto feature. I did disable c-state in Bios, with no effect.

I had a bunch of W10 system updates on the 10th & 11th, about the time my Sleep problem, and...

Re C-State, never heard of this. I will check it out in BIOS, and see. Interestingly enough the sleep problem, and another problem with log-on requirements (which I fixed), happened about the time...

Win 10 Upgrade done a year ago. Everything worked fine. No hardware or software changes in last six months, other than auto Win 10 updates. System always went to sleep automatically per Power...

FYI Not switching MB from existing system. Building new (3rd) System with new components. I suspect your answer is still correct, but just in case...

Had retail win 7 pro installed on two existing systems. Upgraded both systems to free Win 10.
Planning on building new system. If I install win 7, will I be eligible for free Win10 upgrade?

Thanks for good suggestions. Yes-cloning old ssd to new ssd and then installing 10 is what I planned. Keeping Win 7 on separate drive hadn't occurred to me, and is something for me to consider.
...

Win 7 Pro currently installed on 126GB SSD. Only 20 GB capacity left.
Plan to install new 500GB SSD as C Drive.
Plan is to clone 126 SSD to 500 SSD, including Win 7 OS, before installing 10.
Then...