Front microphone jack not working

Hello everyone, hope this doesnt sound to much like a noob question but here goes. I have just had to reformat my pc because of some little darlings dumping some nasty little devils into it But have it all up and running now with no troubles except for this. The microphone jack in the front of my machine no longer seems to excist It worked before the reformat but not now. When i go to sound and recording properties it only shows the mic jack at the rear of my machine. Anyone got any ideas where i went wrong.
Thanks
Steve

Oh its a Dell pc running vista home premium.

 

What is your sound card name? If it is Realtek on recent pc, try to change Front Panel Inputs > HD Audio to AC'97 on the bios settings.