Sound on my macbook is not working, with or without headphones?

So, everything was working fine just this morning, but now, all of a sudden, the sound isn’t working on my laptop at all. I’ve restarted, of course, gone into the sound settings under system preferences and played around, but nothing has helped. Articles have mentioned a red light in the headphone jack, which I do not have.

Any tips on how to fix it, or should I just take it in?