I found out my problem AFTER I hacked my dvd case lid up (making a window

) The white spindle has a magnet in it, and when there is no dvd it sticks to the drive spindle causing it not to open, It was happening way before I cut the lid up, and my only fix was to push the tray in as it tried to eject effectivly loosening the magnet so the tray woudl slide out. After I cut the lid I was able to adjust it a bit so it no longer has problems opening. Hope it helps a bit