Ok so I used to be able to play dvd's in 5.1 dolby digital goodness, but now something has gone terribly wrong. I reinstalled osx a while back and since then it hasn't worked. I just started messing with it today and I'm determined to figure out the problem. I've read all the how-to's on this issue but nothing has worked. I hope someone can help me. So I went to system preferences->sound and changed output to digital out. My tos cable is plugged into the optical out and it goes to my logitech z-5500. In the audio midi setup is where the problem lies. Under the default output the only options are built in audio and none. same goes for system output. i clicked on configure speakers and then multichannel. all the options are grayed out except for stereo. under audio output when i change 2ch-24bit to encoded digital audio it changes the defualt output and systme ouput to none. Also when i close the setup it doesn't save the changes. There are no programs open, so no itunes or dvd player interference. What is wrong. is my os corrupted or something really weird? Anyone got some ideas please help!!!