You may have to take it apart. If the auto-ejection does not function, try right clicking on the drive and hitting eject. Otherwise, get a set of mini screwdrivers and remove the drive from your computer. Remove the top and you should have direct access to the disk you want inside.
The following method only works for drives with a tray, it will not work on slot loaded drives. The drive should have a small hole located near the eject button. Take a small paper clip and unfold it so that it fits in the hole. Push the paper clip into the hole to manually open the drive.
For a DVD or CD-Rom drive, you will need a paper clip. Unbend the clip so that you have a straight piece about an inch long. On the front of the drive you will see a little hole. Isert the clip and push. This will open the drive.