Laptop microphone noises

Hi all,

I have a HP G62 and just recently, the built-in microphone started making noises. I didn't realize this until I spoke to my sister on Skype. She says she can hear loud noises and can hardly hear me. When I click to 'listen' into the microphone and apply, I too can hear a variety of loud sounds. 

Does anyone know what's wrong and how I can fix this?

P.s--While I'm at it...my laptop also sounds like an airplane, like it's working REALLY hard... what's that? 

Thanks