Before you run the game, right click your desktop and click "Screen Resolution" then try (just leave that there in the background), If that doesn't work normally alt tabbing in and out fixes most things.
Yeah works for me.
Don't ask how.
Age of empires 2, is by far one of the best RTS's I used to play at LAN's.
I'm well known with my army of lethal monks. Not a tactic easily done and it's quite funny.