This thread may save you many hours of work. After 12 hours of frustrating trial and error, internet research etc, things are finally all fixed. My setup: windows 10, Xplane 11.4, oculus rift, Realsimgear 530, GTX1070TI, intel i5, 39 inch hdtv, all running perfectly for many months. My graphics card connections were hdmi to oculus rift, DVI-D to main monitor, Realsimgear to display port. For months all,worked flawlessly. Timeline of events. I wanted Xplane’ s Vulcan. I downloaded version .50 and installed it. Xplane opened, stated I’d need to update drivers. I did that through nvidia. Restarted Xplane, checked the Vulcan box and I don’t know exactly what happened but from that point on I was in trouble. I found that my windows desktop screen was upside down on the little Realsimgear 530 and my main 39 inch monitor went black with a no input message. Now, operate your system on an upside down 6 inch “monitor”. It drove me nuts for hours. Device manager showed only 1 PnP device. What happened, how recover? I swapped ports and cable, redid drivers, reinstalled Realsimgear firmware, reinstalled Panasonic VIERO firmware, but no joy! Basically after 12 hours, I had a giant graphics card supporting either a 6 inch screen or a 39 inch monitor, but not at the same time, one or the other but not both. Maddening. As a last resort experiment, I decided to add another monitor to my setup just for the heck of it so I unplugged the oculus hdmi connection and inserted an old Insignia tv hdmi cable into the port. As soon as I did that, boom, all screens appeared!! That’s it. It wanted the physical presence of a 3rd connect, the hdmi. I can turn off the Insignia but it must remain plugged in or, you’re back to one screen! i have no clue as to why. Device manager now shows 3 PnP devices now. Two is a pair, three is company, so...it wants company.