Hey there! It sounds like you're having a bit of trouble with YouTube videos not playing sound properly in Firefox, right? Sometimes issues like this can be caused by the browser's settings or even the sound settings on your laptop. Let's start with a couple of quick steps. First, try clearing your browser's cache and cookies. Then, make sure your sound settings are all good by checking both the sound settings in Windows and your laptop's audio settings. Sometimes it can also help to disable any browser extensions that might be causing conflicts. Give these a shot and see if it helps get that YouTube sound back on track. If you need more detailed steps, feel free to ask.