The monitor
If you can troubleshoot the problem without opening your computer, that is best. So, connect a known working monitor to see if it works. If not, I guess you have to suspect the video card. :)
The Video Card
A monitor is an output device. A touchscreen monitor is different. The touch panel, which is installed over the monitor is an input device, but the monitor itself is strictly an output device.
Put a known good device in that port...process of elimination!
Normally it is an output device. However a touchscreen monitor is both an input and output device.
A Monitor is an output device, but a CPU is not
A monitor is an input device only if it is a touchscreen.
monitor is an output (display) device
out put device
A normal computer monitor is simply an output device; it takes no input from the user. A touchscreen monitor, on the other hand, is both an input and an output device.
monitor
An HDMI cable connection will not work on an HP monitor if the cable or monitor are damaged. Trying a new cable or hooking it to a different device can help narrow down the problem.