Question Is the Motherboard dead?

Jul 20, 2019
Hey guys,
First time for me here.

A week ago I bought used Asus z97-h3d Mobo without checking the mobo (I know you think I did mistake but in my place that is normal).
The guy who sold me the mobo said it was never been used and it's brand new which make sense since the mobo was in it's original package with zero dust or any use marks.
I came home, connected the mobo to the PSU, install my i5 4460 CPU, placed on the 16 gb ram and.... Nothing. No sign of life from the mobo - no spinning fans, no beeping(I plugged speaker to the mobo),no LAN Jack connector light ,even no LED power light on the mobo itself.
i tried other PSU, other RAM cards and slots and honestly I don't think that's the problem.
I even tried replacing the mobo battery.
The only one sign of life I got from the motherboard was when I connected the 24 pin connector and for a split of a sec the fans light turn on and they spin.
For me it's look like the mobo got some sort of electric shock when I connected the 24 pins connector rather sign of life.

I am writing here just as last try to put the mobo back to life before I returning it to the guy who sold it to me.
Is there anything I missed? Is there anything else I can do in order to get the mobo back to life?

my rig:
i5 4460
2x8gb g.skill
Corsair vs550
GPU irelevant since I didn't tried even connect to a screen or something.
Jul 20, 2019
CPU: i5 4460
Motherboard: Asus z97-h3d
Ram: 2x8 gb g.skill
GPU: r7 260x
PSU: Corsair vs550
Chassis: Thermaltake
OS: Win 10

I don't know how old the PSU but I know for fact it's 100% working.(tested with other systems)