My DVD/CDRW drive doesnt read DVD's!

Hi, i need urgent help plz…this problem has been since i bought the computer, and that was 2 years ago lol…well untill now it wasnt very important. I just got a game and really would like to play it, but it is on a DVD disc.The problem is: my DVD/CDRW drive doesnt recognise DVD’s…i can read and write CD’s…but when i enter a DVD disc into the rom, nothing happens!? Its like theres no disc in it.I would really appreciate ur help everyone!