My old gtx 460 NVidia card died so I have a gtx 480 I am trying to use. The power plugs on the 480 are an 8 pin and 6 pin. the 460 had two 6 pins. So I plugged in the two 6 pins into the 480 but I get nothing on the monitor. My 680 watt power supply only has the two 6 pin plugs and no eight pin option. Would there be some sort of adapter I can use. I have a couple molex plugs that are not being used. would they help? this computer is 2 years old. gigabyte x58 usb3 board, intel core I7 960 cpu, 10 gb memory, if that helps.