A little help please

I got no sound. the sound was working fine late night yesterday. i went to listen to some music but i get nuttin. I changed the speakers but still nuttin. when u plug em in u hear a crackle but im getting nuttin. i troubleshooted the sound programs. any suggestions plz

Have you accidentally muted the sound? Have you been into device manager to see if there are any software conflicts that might impede your sound card?