I have 2 monitors plugged into my work PC with HDMI to Displayport cables. Every day after work, I unplug them and plug them into my personal computer running Win7 with a Radeon RX 480 card. I've been doing this for the past 5 months. The past couple of days, one of them would go black for a couple seconds every so often. Last night, it completely stopped working. It still works without any issues with my work PC.
I've tried plugging it directly into one of the HDMI ports on my graphics card. I've tried disabling and re-enabling the monitor in Device Manager. I've also tried rolling back the driver for my g-card and then updating it again. My PC recognizes the monitor and behaves like it's working.