Empire - Map controls not working

It's winter 1784 and suddenly the usual up, down controls (the letter keys) are unfunctional. I was in the middle of a turn, just finished with a battle. Moving the mouse to the edges of the screen do not work either. I can click around the corner-map with the mouse, but that is all. Qutting the game as well as restarting the computer were to no effect. Recently I have experienced a lot more stuttering in the image, and some ground battles lack certain action sounds, and the stop-starting of the movement on screen have sometimes been out of control. I have, however, been able to finish battles successfully.
But now I can't move around on the map. What am I to do?