I have a P7-1414 HP with integrated AMD graphics. I have replaced the PSU with an EVGA 600 watt and installed my Nvidia Geforce GTX 590. I plugged the cable into the graphic card and turned on the computer. I got a no signal. I plugged it into the mother board VGI and got a signal. I have verified in BIOS the integrated graphics is deactivated. Need help please.