Please insert the correct dvd-rom- Sims 2

It sounds like either the CD rom is scratched and unreadable, or you might need to update your computer's CD rom driver. Depending on what type of operating system you have there are different downloads available. Under your start menu, type in "windows update" in the search box. Completing these updates might fix your driver, and if that doesn't do anything, you can find manual downloads online, however, beware of scams and look for only microsoft/mac certified updates.  

Here is a link for Vista Updates, but also gives you a little more info, note it is a microsoft webpage.

http://windows.microsoft.com/en-us/windows-vista/update-a-driver-for-hardware-that-isnt-working-properly

I don't know if this will fix your problem but I hope it helps.