Several problems after H100i v2 dusting

[seaniez]

After reinstalling my H100i v2 for dusting, i tried turning on my PC, but of course I got no signal, fans on. So wanting to get to the bios as fast as possible I unplugged my hdmi cable from my GTX 780 Ti to my onboard graphics. I missed the bios screen and got to my desktop, but I heard the fans of the cooler get very loud, so I checked HWMonitor and it said my i7-7700k was at 93 celsius but the clock was at 800 MHz, I quickly shut it off. I came back about an hour later to turn it on, this time one beep from my Asrock z270 killer and no signal despite being on mobo graphics. Suspecting a RAM problem I removed one of the two 8GB sticks and I got 3 beeps indicating absence of memory, i reseated it and tried the other, same issue. I tried again with both in and the computer turns on for a second, turns off, then on, and I get 3 beeps. I now suspect it is a motherboard problem, but I can’t understand why the onboard graphics stopped working after doing nothing to the computer. I had to replace my previous motherboard after encountering similar problems. What is the best course of action and how could this have happened during the dusting process?

 

[drivinfast247]

Did you replace the thermal paste?
Did you properly reattach the cooler to CPU?