Let's look at a few different ways to figure out how to fix the Code 43 errors that prevent you from using hardware devices.

Fix error Windows has stopped this device because it has reported problems (Error Code 43), for devices for Intel, Radeon or AMD Cards.

I finally check the device manager, and the GTX970 shows with a small yellow caution sign, with properties giving a "Code 43" error. Crap. I uninstall and reinstall drivers, nothing.