Computer freeze/lock up - pink or green screen crash
So my computer has been randomly locking up while playing games and will just freeze. I manually restart and sometimes won't happen for a week or will happen before it even loads all the way back up. Sometimes if freezes whatever is on the screen when I'm playing a game and other times it will crash and go to a pink screen, green screen with lines on it, or a grey and baby blue screen. It is always random so I can't go recreate the crash after trying different solutions. Just recently it has got a lot worse to the point where I couldn't get the computer to boot up all the way without crashing. I stopped trying after a few times and the computer just shut off while booting up and the power supply fan went full rpm and just stayed on until I hit the power button. What's going on?
Amd 6 core 3.5
2 1866 ddr3 ram
Rosewill bronze rates 850w
One thing I think is a main culprit is the motherboard because my onboard sound stopped working shortly after computer was built and the Ethernet port stopped working as well. I took it apart and reinstalled everything and noticed the guy put a lot of stuff in wrong. Power supply was upside down, the CPU wasn't seated and came out with the heat sink when I pulled it out. So I reran everything and installed everything correctly and just put a fresh os install. Any of this information help? I haven't had time to test after all that work yesterday but I can't just go do one thin to recreate a crash cause it's always random.