Before you shutdown to remove the old card and install the new card. Did you remove/uninstall the hardware from device manager?
I would also go ahead and run DDU at this point from safe mode. It should get rid of all the old leftovers from the old card and allow you to install the new drivers successfully.
Then run a clean install from the custom setting when installing the latest driver.
Dont use the Auto detection it can be flawed & bugged with 10. You better off to download straight off AMD site the most upto date driver for your card & install it as a clean install manually. Pay to download DDU first run it threw & wipe any existing display driver, run a registry cleaner which does help 9\10 problems can be solved with a registry clean. Manually install drivers as a fresh install with Antivirus disabled as some anti virus's can over ride & stop the AMD drivers installing properly.