Sims 2 Apartment Life?

I recently bought the Sims 2 Apartment Life and had to uninstall it because one of my other expansions was messing up. Anyway, It had installed correctly that time and several other times I installed it. Now all of a sudden, my computer won't read the cd! It reads every other cd I put in EXCEPT Apartment Life. This has never happened before and (pardon my french) I don't know what the hell is going on! It's so random, please help me!