Doing a CMOS CLEAR or resetting your BIOS back to factory defaults will re-recognize your 5700x3D processor.
Now you can use BIOS Settings to configure your RAM Memory and any other hardware settings.
NOTE: Your OP is very vague without any PC information. Plus you didn't clarify the Display issues you are having.
Do you have no display during POST or bootup or after Windows starts?
Please add more detail to your issue with your display with PC Information.