Purchased Sims 3 but cant play..............

Hello,
I have the Sims 3 and now the CD drive on my computer wont play the game I got to play it one time and the game ran so slow that I gave it up. So when I heard that there was an update for it that would make it run faster I went to play it again and the game is not loading I keep getting a message that says to load the disc in the computer. Okay, my question is that sense i purchased this game already is there anyone out there that knows a way for me to play this game via internet download without using the disc? I have registered the game and i also have my product code please someone help me.