If you have recently updated to windows 7, and your Realtek Hd onboard soundcard, no longer works when you insert a pair of headphones in the front panel,
You might be in luck, there is a work around that seems to work :)
In the Realtek Sound Manager,
On The right hand side where it show’s you a display of the jacks, there is a small folder icon,
if you press a popup is created with a few options,
Select “Disable front panel jack detection”
And press ok and Walla your front panel should be working now, worked for me hihi, hope it helps
Also you might want to check that there is a cable connected from your case front panel to the motherboard socket if this never worked before,
if you assembled the pc yourself or bought an unbranded pc, as sometimes this is forgotten or not done. Most of the Time it’s a black or green connector coming from the
case with 10 hole’s usually one of them is blocked out, and on the Mb you will find corresponding 9 Pin’s to the cable pinout, most of the Times it’s Labelled as Ac 97
Front Panel Audio, Audio Or Hd Audio.