I was playing for a while and everything was working fine. Then I closed the game, took a short break, and then I wanted to play again. But when I press on the play button in the launcher, nothing happens. I tried multiple times but still nothing happens. I tried everything and searched tirelessly for a solution but I couldn't get the game working again. I don't understand how the game was working all the time and then suddenly it stopped working. If anyone can help me fix this, I would really appreciate it. I'll wait patiently for a reply.

Have you tried deleting the cache files ("Accessory.cache" and "groups.cache", posibly also "Contentregistry")? They can sometimes cause the game or Bodyshop to not start, and occasionally also cause crashes or other bugs.

They're in the Documents location (one of these, depending on game version, and generate whenever you're using TS2, Bodyshop or Homecrafter)
C:\Users\...\Documents\EA Games\The Sims™ 2 Ultimate Collection
C:\Users\...\Documents\EA Games\The Sims 2

There's also a "Cigen.package" file. This one has thumbnails for Bodyshop, and can be useful for faster loading of said thumbnails. It will regenerate if you delete it.