Shutdown then Immediately Restarts

Win 10 Pro x64
HP Spectre x360 15t, 16GB DDR4 2400 RAM, 1TB M.2 SSD, NVidia Geforce MX150 2GB GDDR5

I was having some issues with HP printer drivers but that did not appear to cause this shutdown issue. I plugged an LG BE14NU40 Blu-Ray Writer via USB and output via HDMI port on PC to a TV. The system seemed to have issues with video getting to TV and I had to restart. After the movie ended (American Assassin, 3 out of 5 stars, the book was better) I issued shutdown command and the system restarted. I could not get it to shutdown at all so left it for this morning.
I changed Power Settings so that pressing the power button causes shutdown. Absent that I cannot get it to shutdown by command or using nirsoft's nircmd with /s switch. Everything but pressing the power button to kill it results in a restart.

What could be the culprit?

Please boot your computer into Safe Mode and try shutting down your computer from Safe Mode and tell us if issue persist or not.

FreeBooter,
Thanks for the reply. The issue occurs in Safe Mode, as well. Note that this is a new Windows 10 installation and not an upgrade from Win 7/8.

Can you reset BIOS settings to its default factory settings you can do this from BIOS setup utility.

Reloaded factory defaults in BIOS and attempted shutdown: the computer restarted.

Please follow instructions at youtube video and website link below.









How to Resolve Post-Windows 10 Upgrade Issues on HP Laptops ... - HP Support Forum - 5209825

No joy. I followed the instructions and unchecked allowing the computer to save power.
Start menu shutdown: restarts
Command line shutdown: restarts
Single press of power button: restarts (system set to shut down on press of power button)
Hold power button for 4 seconds: shutdown

Make sure to install Windows 10 updates.

Boot your computer with KNOPPIX bootable live CD, DVD or USB flash drive and see you can shutdown your computer from KNOPPIX if you can then we will know shutdown problem cause by Windows 10.

I will perform that operation tonight. (I've got to get back to work.)
Thank you for the real-time assistance, FreeBooter!

You are very welcome!