I can't hear the sound on my computer!

Hello,

I'm having an issue with my sound. The night before i turned down the volume, and everything was fine. Then this morning i try to turn up my volume and listen to music but no sound plays through my speakers. I've checked everything to make sure it wasn't on mute or turned down. Everything is at 100% and my computer states that theres nothing wrong with my computer, but I know there is or else I would be able to hear my music. I can't figure out what is wrong with my speakers. Even when i turn it off and back on I can't hear the sound it normally makes when it comes on. Please help?