I had the CDs for Glamour Life and Family Fun and I installed them too. Well before I had Sims 2, nightlife, seasons , open for business and pets. After I installed the 2 new ones, my items disappeared. I seem to still have the house and people but my items that I bought seems to have disappeared and have been replaced. For example my computer was a custom one I got from this site but now it has been replaced with the default and it is no longer available in the store.
Everything seems to be in place in the downloads folder but I don't know why this is happening.
When adding an Expansion or Stuff Pack you should always install into a clean vanilla game. Because you didn't, the game has automatically turned off all CC (even though it may say it's still enabled). You will need to go through the steps AudreyMay mentioned above a few times for the game to recognise the CC is installed.