Mic Not working on Inspiron 9400

My Mic does not work on my Inspiron 9400. A week ago, when i plugged in a mic, an popup came up with Mic detection and I was able to choose what audio input I can use for recording. Now I cannot get this auto detection to happen. Can anyone tell me how I can get this program to work again.

I tried different mics and also played around with the Mic property settings. I cannot get the mic to work. Any help is much appreciated.

Thanks