You have to decide if yours is or is not under warranty before you proceed. Accidentally bumping the extended drive tray or resting a heavy weight against the drive tray may throw the tray off track, rendering it impossible to shut the drive.

http://www.pcguide.com/vb/showthread.php?t=11670 is a typical discussion where they need to get the door back on track.

Remember this is an area that those who can, will and those that are under warranty shouldn't.

Bob