Need some simple help with my desktop

[DoubleA]

I was playing a game (Tribes 2 if that matters) and I hit a button or a combination of buttons and the game minimized to a smaller screen. I was still able to play, but not at the usual, full screen size. I figured I would try to maximize the screen, but there is no icon in the upper right corner. What did I do and what buttons do I need to press to get it back to normal? Thanks for your help.

 

[Angrymarshmello]

Try Alt+Enter

 

[j0lly]

Restart the game.

 

[DoubleA]

The Alt + Enter worked. Thanks a bunch!