What I have had to do several times over the years is totally swap out graphics solutions to an entirely different GPU brand. That is, AMD is installed and giving problems, uninstall the AMD completely, including the drivers, then install a NVIDIA card and drivers. This forces a total reset of every graphics setting in the OS. Likewise, if NVIDIA is giving the problems, totally remove and install an AMD - or vice versa.
Just make sure you do a total "cold" shutdown, and observe ESD precautions before pulling/inserting cards. That is, unplug the computer from the wall and touch bare metal of the case interior before reaching in to touch any hardware.