Hi Feraty,
please make sure that your front panel connectors are correctly connected to the motherboard. Once it is connected correctly, unplug everything from the mic in, and reinstall the windows drivers. After you have done that, go into the windows sound settings, and make sure that the correct device is selected as the primary device (there will be a HD Audio, and a regular audio device)
If all of that doesn't help, then you might want to contact gigabyte for an RMA.
Good luck