Fans spin for a second then turns off

[Ciggarilo Himself]

On this new build when I plug in the 20pin and the 4pin connector and try turn on the computerthe fans spin for a second then everything just turns off, but when im nor using th 4 pin connector(just the 20pin connector plugged in it powers up fine BUT I get no picture on my monitor)Can anyone tell me how to fix this or do I have to send the psu back also it works perfectly fine with an older psu with both plugged in(I also have tried setting it all up on a wooden desk)this is my first build soI could be missing something simple.

Thanks

EDIT:nvm fixed I was using the wrong 4pin...