Need a little help with a Compaq Deskpro EN SFF
 

Hi Guys and Guyesses,
I recently had to remove the cover from one of these Compaq SFF
computers to instal a pci card but when I put it all back together, the
CD tray sticks inside and won't come out to play.
Is there some knack to closing the case that I have missed?
Many thanks,
Steve