I have a pretty annoying issue: Whenever I turn off my PC, and then turn it on later, it will show the Windows spinner but then the screen will turn black; and the monitors will turn off after a couple of seconds. When I turn it off with the power button and turn it on again, it works fine.

The same thing happens when I do a Reboot.

I'm using sleep most of the times, which works fine.

I did a lot of Googling, and the common recommendation is to turn off Fastboot. I have turned it off via Control Panel => Power Options => Choose what the power button does. Doesn't solve the problem.

Any suggestions?