T61 weird noise/microphone problem?

My T61 has been making this really weird sound today. When I close the lid (to make it sleep) it makes this loud high pitched sound that doesn't stop. I have to open the lid to make it stop. I also noticed that the microphone seems to be on. When I plug in headphones, I hear everything that's going through my microphone. For instance, I can hear myself tapping random parts of the notebook really clearly. I have no program on that is using my microphone. Any thoughts on this?

Edit: The loud noise only happens when I close my lid really fast. If I close my lid slowly and I let the computer go to sleep before the lid is actually closed, then there is no noise. If I close my lid before I let it fully sleep, then it makes the loud noise.

 

Nothing is wrong with your t61.

Your microphone is on, and when you close the lid it is closer to the speaker. It needs
a loud noise (like closing the lid faster) and it enters into a feedback loop.
We need to find a way to make the microphone not play back.
Try left clicking on the speaker icon in the bottom right of the screen, and click playback
options. Here mute the microphone, and see if it solves your problem.