External display lost connection

[E9Luke]

My adult granddaughter uses an HP laptop model 15-dwCO81wm with a Samsung 27" external monitor (Model Code: LC27F396FHNXZA). Connection: HDMI. This setup has served her well for about three years. The monitor was working when I checked the setup two days ago, but she told me the monitor was failing to display after startup. The monitor would start working properly after she pressed the jog button on the back of the monitor. But now the external monitor fails to display her desktop at startup. We can't get it to work with the jog button. 

I've checked the usual suspects—

• The physical cable connection seems secure.
• I downloaded the driver for the monitor from Samsung and tried to install it, but the attempt reported "No driver to install." (BTW: I noticed that the driver was labeled version 1.0, which suggests that the driver already installed is probable up to date, no?)
• In Settings on the laptop, I checked for the second monitor, and it reported No second monitor detected, or words to that effect. 
• I've rebooted the laptop several times—no joy.

So I'm thinking to go back to day one. That is, I'll uninstall every bit of software for the monitor and start over—as if this were a new installation. What do I look for to uninstall? When I first installed the monitor, I went the PNP route, as I recall. Just connected the new monitor and saw it go to work. It was pretty uneventful. I figure that if I can replicate that experience, all will be well. Whatcha think?

[E9Luke]

Never mind. The fix was far easier than I'd imagined. I should've figured it out at the start. I opened Device Manager and noted that there was only one display: the integrated monitor for the laptop. Something had kicked the external monitor out of the system. So I decided to revisit the day I first installed the Samsung monitor. I unplugged the monitor from the laptop and from power. Then I plugged it back in. It started working properly right away. Problem solved.

Oh, yes—I checked Device Manager and, sure enough, the Samsung monitor appeared alongside the integrated monitor. Well, thanks for listening!