|Sounds like your optical device is on the way out.|
Have you tried to right click on the drive icon in windows explorer and select eject? That may or may not work depending on what the problem is with your optical device.
Second, there is a little pin hole in the front faciaof the drive.
You can eject the drive physically by taking a pin and inserting into the pin hole to push the drive door open.
This pin hole is provided for cases where the drive will stubbornly not eject / open.
☺ When everything else fails, read the instructions.