Update:
I re- installed windows 7 totally hoping that maybe that would help... well it didnt.

Someone suggested me to get a USB sound controller, so i decided to give it a try. If the problem was the sound card or the defect mic Jack, this should help right?.... Wrong!!

Headset works fine, but mic still doesnt, however this time the headset microphone is detected on the record devices window which is more that happenes when i plug the mic jack in the sound card directly.

I have check that the mic is not muted and the volume is 100% but still nothing.

I really dont know what to do anymore. It seems that the builtin mic is somehow forced to be the one and only.

Any suggestions please?

Thanks