[NAME] Moodley  And you might also have to press and release (without holding) the "Screen Off" button on right edge of screen, just above the power button, to switch to using the laptop for HDMI video input. 
I want to use my All in one desktop as a second monitor to my laptop. I have an HDMI cord and it doesn't seem to be working, any idea? Do I only have an HDMI out port?  Below is the desktop I have : DELL 60 cm (23.8") Inspiron 5488 Intel Core i7 All-in-One Touchscreen
All in one desktop as second monitor