Try uninstalling it and re-installing it, I've had the same problem with generations, if it still doesn't play then take it back to where ever you've brought it , they may be able to help you ferther. Other things would be checking for minor scratches on the fisc, which can effect your gameplay. Also any recent updates on your computer can effect your game, being that you have to re-install your game so the game may work with your new computer settings. I recommend going to your local retailer for more professinal help...
Hope I HELPED 🙂