GPU shorting out computer

[Finman85]

My new PC build works until I plug in the graphics card then nothing will come online.

I have a MSI z170-a pro motherboard.
Intel i5 6400.
Seasonic 620W m12 bronze power supply
Evga GeForce gtx 970 graphics card

With everything plugged in the power last for a split second; as soon as I unplug the power cables from the GPU everything comes up.

I have tried different power cables and reseating the GPU to no avail.

 

[popatim]

Sounds like either you aren't using the cables that came with the Seasonic, the cables are wired wrong, or the gpu is shorted.