My PSU runs fine when plugged into the motherboard without plugging in the fan cables that run from my power supply to the motherboard, if I plug in the Fan cables then my PSU refuses to start up. So my other components work but none of my fans do and when I try to plug in the cables to the system fans then my PSU refuses to work all together PLEASE HELP! Is it a bad PSU or a bad Motherboard? PS: PSU is a Corsair Gs 800 series