Hi all My 2010 27" iMac's DVD drive accepts discs, sits for 20-30 seconds then ejects them. They don't show up at all in Disk Utility. However, if I boot camp into Windows 7, Windows will mount the discs fine. I left one mounted and rebooted to OS X (Lion), and the disc showed up on the desktop fine. Eject and re-insert cause it to go back to just ejecting the disc. I have tried resetting the PRAM and NVRAM, and I have tried unplugging the iMac for a while just in case... I don't have anything odd running in the background... Anyone got any ideas please?