I'm having this problem that the one (of three) displays are showing up as disabled. If I unplug any one of the other two displays, it switches to the "black" display (i.e. it then becomes enabled automatically). All three displays used to work just fine, but I have upgraded to Windows 10 (from Windows 7 Ultimate), and since then I seem to have this problem.
Any ideas on how to enable this display. It is most irritating not having all three displays as they used to work?