sound disappeared

[jazwan]

My imac has been great i love it THEN i put itunes on today and no sound. No sound on You tube nothing but the sound plays on start up. I've tried apple support not very useful.
I haven't messed or touched any other settings although i did download the new version of itunes.

 

[Walrus666]

Hello,
Have you checked your sound output in System Preferences?

 

[Spawn_Dooley]

Along with what Walrus666 has suggested, try lauching then quitting GarageBand ... I know it sounds unrelated, but many people have solved sound issues this way ... try it, there's nothing to lose ...