'No game disc found! Please enter The Sims 3 Pets game disc before proceeding.'

I followed every step here exactly --> https://games4theworld.forumotion.com/t1171-must-read-how-to-install-the-sims-3-correctly
But each time I click the play button, I get this same message: 'No game disc found! Please enter The Sims 3 Pets game disc before proceeding.'
I have even tried doing steps 3 and 4 over again, but still no luck.
I have downloaded Generations, Pets, Seasons, and Supernatural.
Also, the the bottom of the launcher, the Supernatural and Seasons icons are gray while Generations and Pets are colored.

I would greatly appreciate some help!

Yes, I downloaded the ultimate fix and went through with that update. I then went to the game launcher and updated to the latest version.

//EDIT

What I meant was that I downloaded the ultimate fix and then went
through with the update, then I went to the game launcher and it said it
was the latest version, but I still get the message when I click play.

//EDIT

Okay, I've fixed the disc error, but now the game won't start at all. I
open up the launcher and click play, but it does nothing and closes.
I've also tried to start it by going straight to TS3.exe but that
doesn't work either.

Admin edit: Please use the "Edit" button on your post, instead of double-posting. Thank you!

- ADMIN

Hello,

Please re-read again, slowly: https://games4theworld.forumotion.com/t1171-must-read-how-to-install-the-sims-3-correctly
There's no need to use the launcher for updating.