We have several DC3217BY NUCs (First Generation of NUCs) in our organization. I decided to test the Windows 10 upgrade on one of them. This NUC has 2 displays connected to it. One by thunderbolt and the other by HDMI and have worked well with windows 7. After upgrading, the screens were cloned and the NUC was using Microsoft's Basic Graphics Driver. After windows 10 detected that the NUC had Intel HD Graphics 4000 and installed the driver through windows update, both screens went black. I tried installing the 3rd generation 4000 graphics driver for windows 10 with no luck. I uninstalled this driver and went to the NUC Support page for the DC3217BY and the only driver listed was a chipset driver. I installed this driver and the screens remained blank. I switched back to the Microsoft Basic driver and the screens came back on. I noticed these NUCs have a Windows 8.1 graphics driver. Does anyone have any ideas on how to get a graphics driver working on windows 10 for the DC3217BY? Thanks!
According to our database Intel® NUC — Supported Operating Systems your NUC does not support Windows 10, and reading all the steps you tried, I probably would do the same ones.
To this point, if our window 10 drivers didn't work and the Microsoft Basic driver didn't help neither, I recommend you do the downgrade to windows 7 to make sure all features work correctly.