If you hook up an external monitor to your Mac OS X machine and run Excel 2004 for Mac on it, you might move your toolbars completely or partially over to the second desktop area. If you then remove the external monitor, it is possible for the toolbars to get “stuck” such that only a corner (like the resizing corner) is visible. You can resize them, but not move them back onto your main screen.
You can try to use “Reset” in the View:Toolbars:Customize Toolbars/Menus, but that doesn't work. There's some other reset-to-defaults choice somewhere that I tried (and can't find now) that didn't work either. Quitting and restarting does nothing.
Try going into your home directory (/Users/username) and nuking this file:
/Users/username/Library/Preferences/Microsoft/Excel Toolbars (11)
Upon restarting Excel, they were back to normal location. Problem solved (except for the braindead engineering).