I have an Acer Laptop/tablet running Windows 10 (6 months old) connected to an Acer monitor (1 year old), via an HDMI cable. The monitor was working fine as an extended desktop until a few days ago (for the past 6 months). I checked the drivers; they are all up-to-date. I tried two different HDMI cables and tried connecting to a TV and it worked fine - both cables. I tried changing the resolution, but no change. I was unable to change the refresh rate (a recommendation from another user). I uninstalled/reinstalled the monitor driver, but no change. The HDMI port on the monitor seems to be OK as the laptop recognizes when the device is connected.
When the monitor is connected, the device manager on the laptop only displays "Generic PnP Monitor" instead of the monitor model number "G276HL". In the Settings, two displays will display onscreen, but when I click Detect, the system says it did not detect another display. When I remove the HDMI cable, the Multiple displays option disappear, so it clearly recognizes the input.
The monitor connects to a PC via a VGA or DVI-D connector with no problem.
I have wasted a lot of time on this to no avail. I can't drop my laptop/monitor off to the Geek Squad (or similar) as I cannot afford to lose that time (working on a contract).
Any suggestions, please and thank you??!!!
if it worked then you need to reinstall or update Display drivers from laptop manufacturer website.
and if it didn't work then it must be monitor's problem.
Did you try Duplicate mode / second screen only instead od Extend mode ?
If that is not a hardware issue then you can also try System Restore to restore your PC settings and drivers to before that issue,