So a few years ago I updated my OS to 10.4.11 - when I did this, my optical drive stopped reading DVD's, but will still read/write to CD-R's. We tried an external optical drive, as well as a new one, and still the same problem. I didn't really look into it much, but have recently gotten back into music production, and need to get programs installed via DVD. I have tried the disc utility and it fixed some problems, but it still doesn't work. I put the DVD in, and after a moment it gets spit back out. Please help.