When installing from the DVD, we have become aware that there have been a few instances of a message coming up saying "please insert disk 2" ( there is just the one disk) So if this should happen to you please could you install from Steam by following the instructions on Registering and Activating the game with Steam, on the back of the quick start guide. Repeated for you here :- Once you have opened Steam, ensure you are in your Games LIBRARY window by clicking the link at the top. Click ADD A GAME in the bottom left of the window, then click Activate a Product on Steam. Follow the instructions that appear, and type in the product code when asked.