PS4 Won't show up on TV screen

My PS4, which I've had for about two years, has stopped working today. The light is on when I press it, but it doesn't show up on my TV screen. The controller works fine. I think it might have something to do with how a day or two ago I was using my XBox360, which is plugged in to the same television as the PS4. I had to do some fiddling to figure out how to turn the Xbox on and I'm not sure whether I unplugged one of the PS4 cables while doing that or if I broke it when I plugged this cable

into this box https://www.google.com/search?q=xbox+360... (not my box but my phone battery's too low to take a video of mine so that'll have to do). Help please. I've tried all the HDMI setting things for it, I've tried holding the PS4's on button until I heard two beeps (it just turned on and off again), I've tried unplugging and re-plugging the HDMI cable for the PS4 AND the Xbox… nothing worked. My name isn't Alison Lynch by the way, I just don't want a bunch of strangers to know my real name.