when I play age of empires 3 my moniter is off. but is can hear the sound of game.
System speciication: Windows Xp
ati radeon 9000 pro family
1GB Ram
intel inside pentium 4 - 3.0 Ghz
Probably, you've somehow set the resolution of the game to a resolution that your monitor cannot display.If you cannot get into the game settings, you may have to re-install the game.