PC doesn't restart properly

[i9 4790 HQ]

Hey, I am having an issue with my newly build system(9900k, z390 aorus master, currently no GPU), It does not restart properly. When I use the windows restart button or even restarting with windows updates. It just ''restarts'' but is stuck, pc wont boot into anything, Black screen. No signal. I have to manually force a shutdown and then restart the pc. I cant get this solved... Flashed mobo bios to the newest version... All drivers are good and installed. LEDs show a 91 code which in the manual is stated as ''issue driver event''. I tried everything and I am fed up. This thing cost me a whole lot of money. My mobo: Z390 aorus master

Also save and exit out of bios also is crappy and needs a manual restart.

Thanks

[i9 4790 HQ]

Anyone know how to resolve this?

[MayCris]

Have you tried reinstalling windows? Also check this link https://superuser.com/questions/977834/windows-gets-stuck-at-restarting-screen