Zoom in/Note entry problems

I can't zoom in at all. MuseScore won't let me and I've tried as much as I can figure out to try. I also can't enter notes into the score, especially because I can't zoom in. Even with note entry enabled it does not work. I've had 3 different people look at it and no one can figure it out. I even Uninstalled and Re-Downloaded it. I also cleaned my computer and installed all my updates. Nothing has worked. I need the application for my final exam so the fact that no one seems to be able to fix it is a bit frustrating. I even talked to a technical support specialist. What do I do?