Help with Gears of war for pc

Please help me, i got gears of war for the pc and for some reason, everytime i start the game a error shows up saying that " The DVD-ROM cannot be located. with a red X Please insert the correct DVD-Rom,click OK,and restart the application." it did work a long time ago once, and i bought it brand new from game stop. And all my other games work just fine, but not gears of war. i tryed uninstalling it, and updating my driver. i even looked for patches. but i still cant get it to run. please advise before i take a hammer to my pc. thank you for any help you can give. :4-dontkno :upset: