iMac wont eject disc...

if none of the following methods work, I suggest taking it in for service.

Force eject a stuck cd/dvd

First try the normal methods to remove the disc. Drag its icon to the Trash can in the Dock or select 'Eject' from the File menu.

If you are running a virtual machine, e.g. VMFusion, ensure that the CD is disconnected from the virtual machine. This will sometimes allow the CD to now show up in Mac OS X.

Shut down the computer and start up whilst holding down the mouse button. This may take some time, but keep your finger on the mouse button right up until the disc comes out or the log-in screen has appeared.

If you have Toast Titanium installed on your computer, choose EJECT DISC from the menubar.

Sometimes you can successfully use the eject disc button in iTunes even if the disc is not visible to the Finder

Open Disc utility and choose the disc you wish to eject in the left-hand pane, then click on the Eject button.

Some Macintoshes have a paperclip hole that you can insert a straightened paperclip into, manually triggering the eject mechanism.

Open Terminal and type "drutil tray eject" to eject the disc/tray, and "drutil tray close" to close the tray.

If your computer has an eject button on the keyboard, restart the computer holding down the Option key. When the startup disk selection screen appears, let go of the option key and press the keyboard's eject button.

Source: http://guides.macrumors.com/Force_Eject_a_Stuck_CD_or_DVD

I'm having the same problem. I've had a problem ever since I mistakenly put two DVDs in at the same time, and I think the drive got misaligned with the hold, so now when it tries to eject, it starts to come out, gets blocked and goes back in.

Rarely, the DVD will come out on its own, but most of the time stays stuck in there. I've had limited success trying to use a letter opener or screwdriver to try to guide the DVD out or make the opening slightly larger. Sometimes, the DVD will come out, but again, I'm not sure exactly what the best technique is, so most of the time it just goes back into the drive. Well, it never actually comes out, but you can hear it start to eject, then go back in and spin up again.

Does anyone know of the best way to guide a DVD out in a case like this?

I stuck a letter opener into the disk drive and whenever it tried to push it out I pressed it against the disk and tried to pull it out

UPDATE: I put another disk in and ejected it and the drive is fine and it came out properly