inspiron 5720 grey screen at startup, cycle power and boots to windows, every time

Press power button / restart from windows

  dell logo flashes

   sometimes gear button flashes, sometimes all buttons cycle

then: grey screen

sometimes: press any key  f12 boot options is displayed,  empty loading bar is displayed

pressing any key (including f12) does nothing.

press the power button and the computer powers off

press the power button again and the computer boots to windows:::   EVERYTIME this works.

Computer works fine, no errors, updates fine,....

But, restart, and cold boot require pressing the power button to power off and then on again.

Have scanned for viruses, intend to use deep scanner and test for root kits.

Disabled the swap, and the hibernate functions, no change.

removed, replaced, ram and hard disk, and battery

BIOS is set to efui boot option, only network is displayed.   Had to use f12 boot options to diplay legacy options to boot from repair CD.

Using w8 repair disk now to check for problems:

After a bit: "Automatic repair couldn't repair your PC"   and not log file, or other information.

Any thoughts?  Any body? any body? Beuller? Beuller?