I had similar problem with this model,
Switch off POWER
remove case (3 screws at rear 1 each side) lift outwards from the back
Disk drive has white center, hold this up with your fingers
TAKE CARE DO NOT touch power supply when you switch Power back ON, It is far enough away from the DVD drive for you to do this safely. drive will spin but can be ejected from front button.
Remove disk from tray Switch OFF and replace cover and screws.
Job Done
Papa, October 2009