What just happened to my hard drive?

Alright, so my computer had two monitors, and I got a third one to add. I connected the new monitor, and bootest up a couple times but it gave me BSODs. I did a reinstall, but windows wouldn’t continue after a reboot where is says setup is preparing your computer, but yould go to that when you boot in safe mode and ask to restart. Now the computer won’t boot past the splash screen with the SATA drive plugged in, but works fine without it. What the hell just happened?