PC will not boot with a graphics card installed

[Landon Warner]

Specs:
PSU: Corsair CS750M 750w
CPU: i5 4690k (watercooled)
MB: MSI z97 PC MATE
GPU: GTX 970
2nd test GPU: GTX 645
RAM: 16gb HyperX

While playing a game yesterday my PC suddenly went dark. When I tried to turn it on there was no sign of life. The fans wouldn't even start up. Then I unplugged the power from my GPU and it started up fine. So I thought I had determined that card was fried so I applied for RMA with EVGA. I then got my old card (GTX 645) and slipped it in to get that minor performance boost. The 2nd card has no ports to plug the PSU into. Then when I powered on my computer, the fans started spinning and the LEDs turned on but it never posted, got me into windows, or even sent a signal to my monitor as far as I can tell. So I changed the HDMI cord to be plugged into the card instead of the MoBo to no avail. I also moved the 645 to another PCIe slot and it still wouldn't boot. My question is, will a new 970 fix my problem? Or is the PCIe slot fried. I don't understand why the PC wouldn't boot unless the PCIe is fried and if that PCIe is fried why wouldn't it boot when I moved the 645 to a different PCIe slot?

 

[Hamperking68]

I would recommend seeing if you can borrow a card from someone.

Or perhaps test the card in another system.

That should help you to determine the cause of the problem.

 

[Jwpanz]

At this point, I doubt placing a new GPU in your PC will fix anything. Have you tried clearing your CMOS? If that doesn't work, then your motherboard seems to have quit on you.

To answer your question about why neither PCIe slot would works goes back to the motherboard itself. My guess is that your PCI lane controller fried for some unknown reason and, thus, caused every slot to die.