I wanted to re-install so I put in the SL DVD into my MBP and rebooted, but after about 30 seconds it ejects the DVD for some reason. I tried using a Windows 7 DVD and it boots that fine, so I checked the drive was functioning this way. How come it doesn't take my OS X DVD anymore when before it was fine? I put the OS X DVD into another older computer I have and it saw the DVD just fine as well.