Sims 3 Supernatural Expansion Pack Won’t Install At All

Hi,

I bought Sims 3 Supernatural Expansion Pack for daughter for Christmas. She has been successfully playing Sims 3 base game for months. We tried to install expansion pack and it comes up with an error message saying it cannot detect an installed version of Sims 3 and then just stops. I have tried uninstalling and re-installing Sims 3 base game, but still when I went to install Supernatural it won’t accept that Sims 3 base game is installed. InstallShield wizard starts but doesn’t complete opening before the error message comes up.