660 TI Not displaying monitor

[EmericanZero]

Ok so my girlfriend got the components to put together a new computer for Christmas. I put it all together and boot it up and the monitor is not displaying. The overall PC boots and stays on but the monitor does not display. Things that I have tried:

1. Using different HDMI/DvI wires.
2. Attaching the monitor to my desktop. (Monitor works)
3. Re-seating the GPU.
4. Moving the GPU to an alternate PCIe slot.
5. Double checked the PCIe 6 pin power cables to the card.
6. Put 660ti in my machine, works fine.
7. Put my 560ti in her machine and it does not work.

The specs for the PC are:

Processor: http://www.newegg.com/Product/Product.aspx?Item=N82E16819103727
Motherboard: http://www.newegg.com/Product/Product.aspx?Item=N82E16813131636
Power Supply: http://www.newegg.com/Product/Product.aspx?Item=N82E16817151095
Memory: http://www.newegg.com/Product/Product.aspx?Item=N82E16820231314
Graphics Card: http://www.newegg.com/Product/Product.aspx?Item=N82E16814127696

I am not sure what else to try here.

 

[EmericanZero]

UPDATE: I think it is possibly the the PSU isn't generating enough power to the cards. The 560 and 660 both won't work with the PC. When I leave it on for about 10 seconds a blue light lights up on the 660 (I think the light is supposed to always be illuminated) this leads me to believe it is struggling to go on.

 

[zdbc13]

Try your power supply in her system.