There is no mute button in my computer. I have a windows xp machine with external speakers. My sound is also not playing. When play any music in Windows Media player it shows that the music is playing but there is no sound. Same thing while playing any movie only the video works not the sound. Also I tried to mute and unmute it from Windows media player. But still there is no sound. I think it is muted from the windows sound device button where it is actually located.