Exactly same happen to me when I install board today... I thought What is now...??? but I figure out I didn't install two fans from H100 in pump...
Fast I disable everything... and It was nice to see normal pretty fast boot after I connect fans.
And BIOS ask me to connect 3 pin connector from pump to CPU fan.
Thanks god I had screws for LGA 2011 for H100, I remember that when I start installation... I bought him before several years but thanks god that was series with LGA2011... Maybe you should check CPU cooler connection with motherboard.
Yes you need to disconnect all cables and try again...if same problem continue you will need back up PSU and VGA.
I always try to have them in house.