This might help... Go to START>right-click "my computer", select "properties". Click on the Hardware TAB, click on Device Manager.. When Device Manager opens, look at the list and where is says "sound, video and game controllers" click on the "+" sign. On the submenu, right click on the Realtek audio, click on "uninstall", then
restart your computer and when Windows reloads the sound driver automatically, maybe it be fixed