Acer One 8.9 Netbook microphone doesn't work.

The built- Microphone does not work anymore on my Acer Aspire One netbook 8.9. When I originally purchased one, I had to send it back because the microphone and sound didn't work.

I thought it was a fluke, but now I am beginning to believe that the device is faulty. The sound is choppy, sometimes can't be heard, and is static-ridden. Now the microphone doesn't work anymore,

Any thoughts or assistance will help me greatly.