I have a late 2011 MacBook Pro (15-inch) running High Sierra (10.13.4).
My problem is that the display is blank and external displays connected via the Mini Displayport on the side don't recognize a signal (also display blank/searching for signal). Otherwise, the computer has no other issues: it starts up, runs programs, doesn't have difficulty with the processor or connecting to networks, etc.
How do I know this if the displays aren't working? Well, I was able to blindly start up a VNC server using the terminal and some luck, and can connect via VNC from another machine to see what I would expect to show up on the display (as well as to control it, etc.), which seems strange to me since if it was a graphics malfunction/issue I would expect VNC to also fail to show the display.
What could cause the internal and external display to not function but still allow VNC to display properly?