Hi, I have something similar.
Only because of the black screen on startup, I can never get back in the Windows menu. Now I don't see any possibility of starting up, not even in safe mode (to then undo this upgrade).
I've tried the startup flash drive and Win10-iso on dvd, but both end in Win10 failure messages and auto rebooting.
In short: every attempt ends in the same black screen with a circle of moving dots and a mouse cursor which I can move around. But with nothing to click on, that's not much help....
Any ideas on how I can enter safe mode? Or otherwise circumvent using this graphic driver which causes all my trouble?