Well, II sorted my particular problem !!!!!this way:
Windows 'says' it's shutdown and screen turns off properly, but Motherboardmotherboard still stays running (fans. lights usb etc).
Answer ? I REMOVEDremoved the Samsung USB drivers for Mobile (to connect my Galaxy s6 to PC)
and my PC now actually does proper shutdown AND restarts !!!!
Proved using another drive running WinWindows 10 on same machine but without Samsung Drivers. Windows Event Logs and fiddling with Bios and Hiberfile / Power settings etc doesn't even come in to it, IF you use another WinWindows 10 fresh drive to prove these things.
Simple eh guys ?