My monitor is also turning off by itself

I was rebuilding my waterloop and changing 1 of my videocards bios.

when i was changing the videocard bios, i had the video card and cpu running without any fluid in them for about 5 minutes, i had fans blowing near.

I successfully changed the videocard bios and shutdown. the video card felt hot.

Rebuilt the water loop. I turned it on, i could see the boot logo, but after that the monitor went black.

Reinstalled the OS from windows 10 to windows 8.1.

As the Video drivers were installing the monitor went black.

I Tried to reset by windows profile. that worked for about 10min. then the monitor went black.

Mostly when i try to boot up, it turns of the monitor off after the boot logo. and sometimes i get a error: WHEA_UNCORRECTABLE_ERROR.