I'm running Windows XP. I've checked all sound drivers and they are ok. My indicator light on the right side shows that the sound is muted but my speaker icon in my task bar shows it is on. The slider bar goes up and down no problem and I've triple checked my SoundMax settings etc and all seem ok. Still no sound. I also tried to open the Toshiba PC diagnostic tool but it will not open. I uninstalled it and re-installed it but still it doesn't work.