When YouTube videos won't play, it's usually because of a browser issue. Most of the time, refreshing the page solves the problem, but you may also need to update your browser or clear the cache.

Most computer issues that prevent YouTube from operating can be resolved with a simple restart. It's possible that you'll have to upgrade your PC at the same time.

Problems with the internet: Local networking issues can usually be resolved by disconnecting and replugging your modem and router. Lowering the YouTube video quality will also help if your internet connection is particularly slow.