My pc doesn't run

[Abdusalam]

Hello Dear friends
My pc doesn't wanna work with its psu and works with other one?
I have a sharkoon wpm600 psu
I tried to short it and connect a fan with it, the psu worked but the connected fan not.
So, I had to try another psu and i have tried the be quite 650w and the pc didn't work.
Then I have borrowed an old HEC psu 350w which is not enough to run the whole pc parts cause I have:
MSI 970 Gaming
AMD FX 8300
KFA2 GeForce GTX 1060 6GB OC
an HDD + SSD
Corsair H105 water-cooling
Corsair vengeance 4×4
So, I have only connected the motherboard and the cpu and the RAMs and the SSD and a fan but not the GPU cause this old 350w psu doesn't have a GPU cable (it's too old)
So the pc ran perfectly for sure no image cause no GPU is connected but overall it ran.
So I decided to test one more PSU
I got myself a cheap second hand psu (super flower 550w) and it didn't run.
I have tested it by shorting it and plugging a fan and it worked.
I mean it's crazy people!
I got enough from this.
What's the solution?
I should mention that I took my pc to a stupid F*ck!n Store to see what the problem is and he told me that it's the motherboard and it wasn't, cause I bought myself a new same motherboard and I've repeated those tests.
Please help me to figure out what is happening???!
Thanks already

[Arcanekitten]

This thread if you haven't read it might help.

 

p.s My PC doens't run either. It does boot though.

[Arcanekitten]

1 minute ago, Arcanekitten said:

This thread if you haven't read it might help.

 

p.s My PC doens't run either. It does boot though.

Adding my thoughts though. 

Most likely the motherboard if the PSU does work.