Sims 3 launcher sais disc not found.?

When I open the Sims 3 launcher (start-up) and click the play button it says disc not found. I can't find my base game code and case to reinstall it. Today I downloaded generations, world adventures, fast-lane, and high end loft. I used the codes from my friend and on the sims 3 website said you can use the same cd and code twice or more. Please help!!!!!!!!!!!!!!!!!!!