Well, as stated I always have images. Have been doing that for a very long time. Multiple backups. I have backups in different locations also. I am OCD with backups....BUT, My issue was I wanted to try and understand what happened.
Call me curious I guess.
 
But, also as stated, running SFC in safe mode seemed to be the fix for me (with the Win 10 Pro dvd loaded)
As mentioned by abacab above, I quote, 
" Windows keeps a cached copy of protected system files in a compressed folder at %WinDir%\System32\dllcache that it can restore from if necessary." That is good to know.....Thanks for that
 
 
 

I trust SFC. That is good insurance against a corrupted system file. 
 
But I have never really trusted the Windows restore points.  To me that may be one way to get your system booting again, but can potentially leave loose ends and some applications out of sync timeline wise. The restore points can restore your registry and system files back to an earlier time, but application files are not touched.  So after you roll back, you need to figure out what needs to re-installed that you may have updated since the restore point snapshot was taken.  Those registry entries would now be erased.  In this scenario, I much prefer a full image restore, no loose ends...

Half the time System restore does no t work. Very unreliable---I agree...........