"Load" is in the "File" menu. There is no such thing in any tab. Also, you mention that "any other buttons" don't work. Are you referring to actual BUTTONS on the TABS or other MENU ITEMS in the "File" MENU? Regardless, I think this problem was mentioned before by someone else, but I have no explanation for it. Do other programs on your computer not function correctly?
Edit: The operating system you're using and whether or not it's 64 bit may be helpful as well.