Answer:If you use AC'97 front audio panel, please install it to the HD audio header as below:
A. Connect Mic_IN (MIC) to MIC2_L.
B. Connect Audio_R (RIN) to OUT2_R and Audio_L (LIN) to OUT2_L.
C. Connect Ground (GND) to Ground (GND).
D. MIC_RET and OUT_RET are for HD audio panel only. You don't need to connect them for AC'97 audio panel.
E. Enter BIOS Setup Utility. Enter Advanced Settings, and then select
Chipset Configuration. Set the Front Panel Control option from [Auto] to [Enabled].
For Windows^® XP
F. Enter Windows^® system. Click the icon on the lower right hand taskbar to enter VIA^® ADeck. Click "Mixer", select "Front Microphones", choose "Front Mic Boost", and leave.
Like below picture:

H. If you want to hear your voice through Front Mic, Please click "Mixer", select "Play Back", choose "Front Mic", and leave.
Like below picture:

For Windows^® Vista™ / Windows^® 7
F. Enter BIOS "Chipset Settings" page, manual [Front Panel] to [Enable].
G. Enter Windows^® system. Click the icon on the lower right hand taskbar to enter VIA^® VDeck. Click "Front Mic", select "Default Device"
H. If you want to hear your voice through Front Mic, Please click "Speaker Output" icon.
Like below picture: