This article was originally written in 2006, but the solution below still (in 2017) applies to Mac computers with optical drive.
Earlier this evening I inserted a blank DVD into my MacBook Pro wanting to burn some files. However, OS X never recognised the disc, nothing on the desktop, nothing in the Finder, not even in the Disk Utility. I pressed the Eject button, pressed and held F12 for a few seconds, but the disk was stuck.
I had a DVD stuck once before, even though recognised by the system, and I got it out after tilting the computer 45 degrees forward. But this time, whatever I did there was no eject mechanism sound at all, just a very quiet sound of the disk spinning up and slowing down every few seconds.
So I decided to use good old trick of holding down the mouse button while booting the computer up. Rebooted, held the trackpad button down – but nothing. Even more interesting is that the computer wouldn’t start up at all.