As you said, one way would be to change resolutions.
Try putting the mouse cursor either on any side until you get a black double sided arrow or any corner until you get the same arrow but facing diagonally (easier to resize that way).
You can now drag the program to make it smaller or bigger by holding the left click down and moving it any direction. This should allow you to resize the window so you can see everything.
Once resized, you may be able to maximize it, and have it take up the entire screen.
