It's TheBryster's Fault!!  Seriously though Boofy,  I haven't seen quite this problem before. This does look kinda like an OpenGL glitch of some sort, or a video driver prob. I had a problem with disappearing menus on my old machine, but haven't since I built a newer system with a much better Video card. Do you have this installed on a newer machine?
 
From what I can see from your screenshot, you can still see your FILE Menu header at top left of screen. If you can click and open it there's a setting you can check  underFILE>Preferences>Application>3DView, which can switch between the software preview and the OpenGL. It can't hurt to try switching from one to the other to see if that might help clear things up.
 
If that doesn't help, I would recommend trying out this question on the denizens of the Carrara Forum because they in truth would probably be able to answer this question better Than I. Besides, dear girl, we don't want to give TheBryster any excuse to shift this whole thread to another Forum just because you asked a question about that app, lol. This thread has turned into a thorn in his side, and we want to keep it there, haha! I'm enjoying my "heretic" status way too much!