Cant Hear :( ( Volume/Sounds)

Hello 😁 I can't hear my Sounds/Volume in my Macbook Air and when I see my Sounds/Volume its in the Maximum power but still I cant hear 😟 .My Itunes is always keep on shutting down or quitting UNEXPECTEDLY. Well I dont know if I deleted something Important about Sounds File and pls Let me know if i really deleted something Important, I will download it as quick as i can to get back my volume or Sounds .This what happened first about my Itunes my Itunes Locked in an another file and it need a Written permission. I surfed the Net how to unlock or to have the Written Permission and yeah~ i think i Unlock it. Then the next thing is My Itunes is always shutting/quitting UNEXPECTEDLY 😟 PLs HELP ME ~ Huhuhuhuhu

Thank You 🙂