Lost Old Sims when Installing Sims 2 Nightlife

[tonijw]

After installing Sims 2 Nightlife, I get a screen that says create new neighborhood. I backed up my original Sims 2 Data that I would like to use. Do I have to start a new neighborhood, or can I used the old one with the families that I have saved?

[ManagerJosh]

Did you open your game after you installed Nightlife to see if you lost your Sims?

[tonijw]

This is what I did. I went to Sims 2 nightlife and then it asked me to create a new neighborhood, I didn't have any neighborhoods there. So then i went to Sims 2. It told me that I was running the wrong version and I should be running Sims 2 nightlife, so I can't get to the original installation of Sims 2. Am I doing something wrong?