Why does my laptop screen minimize when I shut my computer? Help!

I have a Dell Inspiron E1705 and whenever I shut the laptop while it is on and then re-open it, the screen minimizes itself and is surrounded with a black border. Does anyone else have this problem? For the life of me, I can not figure out how to make the screen full size again without shutting down the computer and re-starting it. Please help, anyone???