Recently lost all sound (startup gong, alerts, all sounds) on a MDD DP 867. First I tried hooking up external speakers, nothing. Since it dual boots, tried OS 9.2.2, still no sounds. Went back OS X 10.4.11 and now have a silent Mac. Any other checks to run or is there a PCI sound card I could buy. I just need something, the user watches many Lynda.com videos to learn InDesign and now is forced to another office to view. Or is this a more serious problem. Any thoughts.