Have you gone through the BIOS and looked for a setting change that will activate this feature?
I have been through the BIOS many times and there are only 2 options for the onboard audio.
One is entitled "Onboard Audio" and has two options Disable and Enable.
The second option asks if I want the Front Panel HD Audio enabled or Disabled and since it came enabled thats the way I have left it.
Is there a front mic input as well as in the back? If so, perhaps only one of them works. Try them both and see.
Yes, there are front audio inputs but I do not have that connected to the motherboard so they do not work.
Does the mic work in a different computer? You need to know this for SURE.
Yes the mic does work on other computers and it worked on this computer but when I had my Creative X-fi Platinum sound card installed.