So I just got a new CPU (i5 8400), motherboard (gigabyte h370 hd3) and 2 sticks of ddr4 memory (4+4 at 2400mhz). I booted the pc and installed Windows 8 and then did an installation of Windows 10 without using a key. Everything works fine but when I put on my graphics card (amd 7900 series) the...