Lost cd

I've had that issue in the past with Sims 2.  I talked online with a customer service rep and since I registered the game they just gave me the computer download version for free.  If you have the game registered and or have the key that came with the disc just chat online with a rep and they should be able to help you out with that.  If you get the stuff packs you still need the original sims 3 game and even with some of the expansion packs you need the original disc but some of them like the seasons and university life I believe you might get away with not having the disc.  I would recommend signing up for Origin it will keep all your games stored for you online and it's free.  All you have to do with the discs is register them and they will be stored automatically.  I had gotten rid of my computer where I had the games downloaded previously and lost both discs but because I registered them in the community when I signed up for origin they showed up and I didn't need to repurchase to download them.  You just have to use the same email you used when setting up your sims 3 community ID for origin and all the games that you have registered will show up in your queue.  I hope this helps.