Please Help Me! Sims 3 Won't Start

I have been trying for hours to get the installation of The Sims 3 Complete Collection right for the past few hours.

When I try to play the game and try through the launcher it says that I need to insert the game disk. It also does this when I try to play it without using the game launcher. I have applied the fixes and followed the # Installation Guide and the *MUST READ*, but I can't figure out what I have done wrong. It loads the game fully but then when you are about to choose a city it tells me I don't have the disk in.
(I have downloaded all expansion and stuff packs except for Pets, Movie Stuff, and Into the Future)

Please help me, I have no idea what I have done wrong!
Thank you!

Hi there, @Ourotree, and welcome to the Games4theworld Forum!

Sorry for the late reply. Did you make sure to apply the Ultimate Fix correctly, following the guide here?
https://games4theworld.forumotion.com/t1171-must-read-how-to-install-the-sims-3-correctly#
That error is most probably caused by applying the Ultimate Fix incorrectly. So, please re-do the Manual Patch and Ultimate Fix, and let us know how it goes.

Good luck!