Try updating the game from the offical site:
There are a few patches to fix problems!
If this doesn't help, try and lower the resoloution the game is running at (in the game settings). This is just a hunch, but you never know.
EDIT: Age Of Empires 2 is rather old. I'm sure the systems capable of running that
Especially if it can run the original one without the expansion.
I hope this helps