I'm having the same issue..
Asrock z170 gaming i7
i7-6700K
Gigabyte GTX 1070 Xtreme Gaming
Updated mobo bios, Windows 10 via VNC
To update driver for GPU, I set onboard graphics as primary and GTX1070 as secondary. No output from GPU onto monitor via HDMI (it would display mobo bios, etc. just no dice with passing through VM). Accessed VM via VNC, installed updated GPU driver from Gigabyte. Still nothing.
Looked under device management. Gives error "Windows has stopped this device because it has reported problems. Code 43." Tried updating further but says I have the latest driver. Stuck here. Any advice would be appreciated.