XFX R7800 Series Issue

[KloniaX]

I've replaced my graphics card (nVidia GT 740) with a new one (XFX R7800 Series Ghost Thermal Technology)
and I can't install the drivers for it.
I ran DDU, replaced the GPU, plugged in the 6 bit connector, but I can't install the drivers for it.
I downloaded the AMD Radeon HD 7800 drivers (I think these are the correct ones?), but when I try to install, it says that no supported AMD hardware is found.
When I check dxdiag or GPU-Z, it doesn't show the gpu I put in, but rather some Intel stuff. (I have an Intel Pentium G3258 processor.)
Can I have done something wrong, and is there anything I can do to fix it?
https://gyazo.com/bb81b35c8803d42ec470248bf65752a7

 

[dontlistentome]

I'd do this: Shut down the computer. Remove the videocard. Connect the motherboard to your integrated graphics port. Boot up into Windows. Download the latest AMD drivers(currently Crimson ReLive Edition 17.2.1). Shut down and install the card. Boot up again, this time into your motherboard bios. In the bios look for the advanced menu that shows you your graphics card and integrated graphics information. If it's not showing your 7800 here then Windows will not see it. If it does show your graphics card here then disable the integrated graphics and save your changes and exit. Now connect the monitor to your videocard output and boot to Windows. Install the drivers.

 

[KloniaX]

Your name conflicts with your answer. Are you sure I should listen to you?