Cannot record sound via mic

I am having trouble recording sound.

When I use the front mic jack on my Dell 9150 I can record sound (but the
video in my screen captures is bad - removing the mic means clean video).
However, when I use the mic jack in the back of the computer (integrated
sound card) the computer will not recognize the mic and I see in my device
manager an "unknown device." Sound works fine (I can hear music and play
videos), just the mic won't work.

Any ideas?

Jeff