My tv has just randomly stopped working

Sounds like a good first step, but if it didn’t help, there’s a whole page of troubleshooting steps for TVs that don’t power on. Although a couple things I would make note of before you dig too deep to make sure you’re in the right neighborhood.

The page mentions it, but be sure your TV is plugged directly into a good power source (outlet, surge protector, etc…).

Check and make sure you actually have no power. Are any lights coming on? Do you get any sounds? I would test with a video input you know it will try to use (your Xbox is a good bet if that’s what you last used). If that’s the case you‘re getting power, but not video.