So the horizontal deflection on my AppleVision 1710AV has been playing up for a while, so today I decided to open up the monitor and have a look. I've been following the Apple Service manual, and I have the sound enclosure, as well as the microphone off (which is no big deal, I actually fitted them originally, as it was originally a 1710) I've also removed all the screws from the sides of the monitor (and broke two of those STUPID screw covers in the process :-/ ) as well as the two from the bottom. However, the case does not want to come off. It seems to be catching somewhere around the top. How can I get this blasted thing open?

Thanks in advance.