Windows 7 Start Menu Won’t Work

I’m having a problem with my Start Menu. I can click on that start button, but no matter what I do, I can’t click on anything. The cursor blinks in the search bar at the bottom of it. If I try using the arrow keys to select something on the menu, I’m not able to. Even if I click on shutdown or Control Panel, it doesn’t work. Nothing on there gets highlighted. The only thing that works is I can click on my picture in the upper right-hand corner which brings up User Accounts. How can I get functionality in the menu to work again? Thanks.