suspect a windows 10 update has corrupted your driver files, just like so many others have already suffered recently. Reload the proper driver files from HP for your computer. If the problem continues after that, let us know. Be sure to get HP's supplied video/graphics driver files installed.
I have an HP desktop running windows 10 with dual monitors which have been working fine for many months. Yesterday, I had 2 blank screens with floating "input not supported" message. After a little troubleshooting, I found that HDMI 1 is not working.
If both monitors are plugged in, - blank /floating message.
if either monitor is plugged into HDMI 2 and nothing in HDMI 1 - works fine.
If either monitor is plugged into HDMI 1 and nothing in HDMI 2 - blank floating message.
So, both monitors are fine. Both cords are fine. and the driver must be fine as HDMI 2 is working. If there any idea on how to reset / turn on / repair HDMI 1 or is my only option to get it replaced?