Solid white light after plugging in

Hello, I have a Xbox one S I was gifted from my dad. His GF's daughter dropped it, he replaced the fan and that's when it was gifted to me.

When I plug it in the power button immediately goes solid white, no response from the button or on the TV at all. I've taken the HDD, Disc drive and power supply out and I do not see any cracks or flaws on the motherboard, but I'm a novice so I don't know exactly what to look at. I replaced the power supply and I still have the same problem.

What could be my issue?? Is there a tool I need to check power outputs??

Also, new power supply won't come back out, I couldn't get it out of the holes in the corner. TIA!