Computer Grounding Issue & Invisible HDD

As the title implies I'm currently having 2 issues, the first major issue is that my PC is turning on/off and which the second is that my other hard drive suddenly up and disappeared on me.

1. My computer started to turn on and off on me for no reason while I was trouble shooting my initial problem of the HDD when I fiddled around inside my case. Eventually ripping everything out of the case and "card-boarding" the motherboard, which it worked and stayed on and as I gradually put everything back together it was all good, until I sat the motherboard back onto the brass/copper studs that sits inside the frame and screwed it in. At that point my computer started to turn on and off again which lead me to believe it's some manner of a grounding issue. I have no clue on what to do at this point about going about this, should I just get a new case made of plastic? My current full tower case is all steel.

2. While I was watching a movie which was stored on my second hard drive is started to freeze/lag/repeat all that good stuff on me. It froze my computer up completely and I was force to hard reset the computer, when I booted my PC back up I found that my second hard drive had up and vanished on me. So I went into my bios and saw it "working" I switch to ACHI to see if it'll make a difference but I got a BSoD so I left it at IDE. At that point my computer gave me the option to "repair windoe files" or start normally. Both options made my computer get stuck on the loading screen, thankfully safe mode boots up fine. So what could had caused this and how may I go about fixing it.
 
I also swapped out the PSU with a spare I had lying around, didn't get any power from it so I reused my old one. Now I don't have power from that one either. So besides the "missing" HDD and a suddenly a "no longer working PSU "I'm assuming the motherboard is bad, opinions?
 
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