I recently got a Dell Inspiron 5558. It runs on Windows 7 Professional.

When I'm using Skype, the microphone doesn't pick up my voice, so I went into the control panel and looked at it's properties to see if changing anything fixed the problem. It didn't, so I set the default settings back. 

Why does the internal mic mute itself, not just on Skype, but in my settings too? How do I fix it?