You May have 'chewey' bits of old drivers left in your Windows/ Registry. Don't know what you do know and what you don"t; and I don"t know what you tired. This is about an hour for a full fix assuming all is well hardware wise. >>>.
But first... Google "Boot to BIOS via Windows (or on Boot up, upon pressing power button. Hold down the DEL Key (while dabbing F2 usually). Thus >>>
1) Boot to BIOS and select "Load Optimized Settings" (or whatever your PC uses [my key is F6]) Then click SAVE (mine is F10), and then as/when Saved, reboot. To Windows. Then set your PC to a maximum of 1080p for now.
2) Google this Driver uninstaller >>> DDU <<< , and install it (DDU) & use it to COMPLETELY uninstall completely any old driver &/or driver bits left around. On completion, PC will reboot.
3) Then; on re-boot use "CMD" Run as ADMINISTRATOR (secondary click to mouse for the choice), and run ' SFC /scannow ' (without the " " ' '). That should fix a few issues.
4) Then exit CMD; and go to 'Update Windows'. Still using the Windows Driver (not your GPU Driver). When Windows is fully updated. Reboot. Check.
5) Then (assuming your GPU is plugged in and working; boot to BIOS using whatever method you prefer (hold down DEL on re-boot).... and go to the BIOS Hardware menu and select the 2nd Option that is NOT 'iGPU' (different motherboards & makers use different lettering for Graphics Cards lettering; but it is the one that is NOT iGPU which is the other one you want. F10 to save, and reboot.
6) That should use the GPU as a basic driver for the screen; and now you need to download the AMD Driver. Some PC's have issues with the AMD selected driver; but you can download the AUTO-DETECT AMD GPU which can be downloaded from trusted sites. Run that. That should install the correct driver/software. Re-boot. Check.
7) Some people then go back to BIOS and wreck things again; some go there and select RAM XPG mode or Optimize or whatever. Do what you do; and hopefully it works.
