First of all.... INFORMATION REQUIRED WHEN POSTING A QUESTION
This will help other to figure out if your system can even run the new graphics card.
Go into the system BIOS on start up and ENABLE the PCIe slot the GPU is plugged into. (If necessary)
The GPU should be plugged into the first PCIe slot.
Your monitor or other display device should be plugged into the GPU not the motherboard.
There are either one or two power plugs on the back or top of the GPU these will need to be plugged into the power supply.
(I'm assuming your power supply has enough power to run the new GPU)
Sorry about that, I didn't see it. I really don't know how to even find half of the things required though but if you really need them and you told me how to I could find them possibly.
I don't know how to check my power supply either.
My computer is seriously old so I don't know whats in it especially.
But from what I know is that I have done all of what you said on there.
Slight problem, my PC is linked through an Elgato which I use to record videos and the Elgato is plugged into my main computer screen, a old laptop that controls whats being recorded and the PC. There's another screen that is directly plugged into the power board and the GPU though.
I could try rewiring the plugs possibly.
Sorry if this is really confusing, I'm trying...