I was having a similiar issue upgrading from my integrated graphics to pci on an older PC with windows 10. The new card, Radeon 5450 was working fine until I updated the driver in windows. Removing the pci card got me out of the black screen so I was able to uninstall the amd drivers and software. After reinstalling the card in the pci slot, I booted into bios and enabled the new card. It's worked fine ever since. I'm afraid to update the driver but I might do it when I have time to deal with the repercussions.