to make the front audio work you have to remove the 2 pins on the Front panel audio header pinouts in the picture, then plug the front panel cord in. when you remove those 2 pins the board, the audio on the back also changes. do you have those 2 pin inserted? I know that you don't since you pulled the card out. take some pins off of a old hdd or dvd rom and put them in the same spots shown in the picture.
an idea of how the front pin on another mobo work
Desktop Boards - Front panel audio header pinouts