Troubleshooting - PC Case causing automatic restart.

[Shahrukh Khan]

Hi, 
I have been facing a weird issue for the last few months. I have mentioned my specs below. My PC was working just fine. I built it all new in July 2018. After 2 months it was built I faced the issue with the power button. The power button had to be pressed almost 3-5 times to power on. Then almost 3 months ago when I turned off my PC and went away after a while I saw it powered on again automatically but it kept going through the boot loops. I switched off the main power and kept using the computer but after a while this issue kept showing up again and again. If I leave my PC connected to main power it'll keep powering on automatically. It's not AUTO WAKE  UP on LAN issue as this option was turned off. I even removed the power headers from motherboard and it kept powering on automatically so not an issue with the power. So after alot of troubleshooting I finally teared the whole build apart and put it back together on motherboard box and tested all the scenarios and it was working like a charm with no issues. So it turned out to be my case is the issue now I don't know if it's the issue of power case leaking earth or it's an issue with the power button board. So what do you guys think might be issue? Is my troubleshooting result is right? and what should I do next?
Thanks in advance. 
Regards
Shahrukh Khan

SPECS:
MB: Gigabyte H370M DS3H
Processor: Intel Core i5 8400 - 6 Core 6 Threads - 2.8 Ghz
Ram: Corsair Vengeance LPX 16 Gigs (8GB x 2) DDR4 2400Hz
GPU: MSI GeForce GTX 1060 GAMING X 6GB
Case: Corsair Carbide Series 275R
Cooler: Cooler Master Hyper 212 LED Turbo
PSU: Corsair VS650
Storage: Seagate Firecudda 1TB SSHD
LED: Viewsonic VX2476-SMHD 24 Inch 1080p HD Bezel-Less IPS Display
Mouse: Corsair Harpoon
Keyboard: A4Tech Bloody B328-8 LIGHT STRIKE GAMING
UPS: Stabimatic Gemini UPS - 650VA - Black

[Sjaakie]

13 hours ago, Shahrukh Khan said:

I even removed the power headers from motherboard and it kept powering on automatically so not an issue with the power.

What do you mean by this?

 

Sounds like an issue with the power on / off cable from your case.

[Shahrukh Khan]

8 hours ago, Sjaakie said:

What do you mean by this?

 

Sounds like an issue with the power on / off cable from your case.

I removed the power button cable coming from case and attaching to motherboard. It still kept powering on.

[0x1e]

18 minutes ago, Shahrukh Khan said:

I removed the power button cable coming from case and attaching to motherboard. It still kept powering on.

Sounds like the case isn't grounded to the PSU.

[Shahrukh Khan]

56 minutes ago, 0x1e said:

Sounds like the case isn't grounded to the PSU.

Am I missing something. Can you tell me how to ground the case with PSU

[0x1e]

On 1/15/2020 at 10:32 AM, Shahrukh Khan said:

Am I missing something. Can you tell me how to ground the case with PSU

You can get a wire that touches the case to the PSU.
A cheap way is to wrap the copper around a screw and screw it in both sides.
If that works then you can make it look more pretty later on either with a wire or touching bare metal on both sides.