New pc. But I’m getting black screen.

[Zerohide1]

Hey guys. Have just upgraded my pc and I just finished putting everything back together, I then put power on and everything lights up as it should. I then start it up and it does start up fine. But there noting on my screen it’s just saying no DisplayPort found what can the problem be? I have changed my motherboard to a asus rog strix Z390-F but I have the same GPU a GTX 1080. It also have a brand new cpu i7 9700k. 

[emosun]

The 9700k isn't supported by the boards stock bios so I'd probably start there

[Zerohide1]

How do I fix that? What should I do about it when I can’t get any signal to my monitor.