1. Insert DVD.. click install.
2. It will start install STEAM. (u have to create account if u don't one)
3. Then it will download "prepare the file for installation)
4. Then it will start download the game.
5. Cancel the download.
6. Insert again the DVD.
7. Click Reinstall. It will install from the DVD (takes about 30 min).
8. Click STEAM icon, it will update the game (5 min).
9. Play the game...

Hope this help...