New PC turns on automatically with PSU switch and won't turn off or boot BIOS

[Chmacle]

I just put together a new build with a Ryzen 5 1600X, ASRock AB350 Pro4 motherboard, Radeon HD 7970, 600W SeaGate PSU. My HDD, Graphics card, and PSU were all on a build I have been using for the past few years so they definitely work.
Since I'm using my old HDD and am using a new mobo and CPU, I decided to to a fresh install of windows and clean the hard drive. On first boot, my computer successfully opened my old HDD and OS and from there I went to click setup.exe on the Windows 10 CD and windows began to scan and install. After about ten minutes, the display went to black and the computer may have attempted to reboot. Anyways, the system is now on (lights and CPU fan on) and my monitor is not displaying any activity. Further, the computer won't manually turn off from the power button or the reboot button (both had worked prior) so the only way to restart it is to turn off the PSU. After turning the PSU back on, the computer immediately turns on again without any prompting but still displays nothing. Haven't seen that before.
I have removed my mobo and checked for anything underneath, and there was nothing. Replugged everything back in and it's behaving the exact same way. Also, mice and keyboard are not lighting up even though they were before.

Does anyone have any idea what is going on?

 

[bluechim]

There are 2 things that could be wrong, its either your HDD is faulty and you will have to replace it or you CD Drive doesent work and you would have to replace that you will just have to try and see which one is broken

 

[Chmacle]

There are 2 things that could be wrong, its either your HDD is faulty and you will have to replace it or you CD Drive doesent work and you would have to replace that you will just have to try and see which one is broken

I doubt either of these issues would cause what is currently happening since BIOS doesn't occur and the problem persists in the same manner even after unplugging both the HDD and CD Drive. What really puzzles me the most is the computer automatically turning on fans and lights when the PSU is flipped on and the power button does nothing. Especially odd since it all booted to desktop just fine before initiating the Windows disk setup.exe .

 

[Chmacle]

Ended up using a voltmeter to check that the PSU was fine and swapped out the CPU to find out it was fine. Ended up being a faulty motherboard and requested a new one which solved the problem.

 

[itsallpoo]

i was going to ask if you dropped a screw in the case and something is shorting. God how many times have i done that in the past and it behaved just like that.