Dell Optiplex 760 sff

Hey, i wanted to upgrade to a decent display adaptor so i went through the process of making a few case modifications to accommodate the gfx card im using, and lastly i went out and bought a 500w psu however, the actually dc socket on the board is not the standardized socket, its like a miniture version of one, same shape but miniaturized. Some of the wires are different colours too. Is there some kind of adaptor i need to get or should i start snipping wires? lol :)

thanks :)