Installing more than one expansion...

So I managed to successfully download the base game. However, whenever I install a new expansion (in my case Seasons, Supernatural, and Pet), the new expansion replaces the older one and I can never have all 3 at once. I've applied the Ultimate Fix but I still have the same problem.

To try to keep your problems to one open topic, so we know what has all happened and all can track your progress.

Please do your replies to here, I'll quote you there also.
https://games4theworld.forumotion.com/t9095-dragging-and-dropping-the-exe-and-dll-files-help