Mixed_dcKeyPHD

I don't know why but for some reason just by having connected my GPU (gigabyte GeForce GT 1030 2GB Low Profile) to my pc it won't show anything, even when my monitor is connected to the onboard graphics, when i have my graphics card connected to my motherboard it is just pure black. I have had my graphics card for some months or so and it started doing that yesterday. I would be extremely grateful if someone could help.