Sims 4 Won't launch (bought on steam)

@PumkynPie

Does the game stop working after pasting the saves folder or only after adding CC and mods? If it stops working after adding Saves folder, the reason is not the computer, but a broken Saves folder, most likely due to outdated CC or mods that were no longer compatible with the game after the update
If the game stops working after pasting the saves folder, it means that the old saves folder is broken and unfortunately cannot be repaired. The old library - the Tray folder can be left in the new game folder, but the old saves folder must be deleted.
Since probably some outdated mods or CC caused this, if you want to use mods and CC you have to find the culprit, otherwise when you put old mods into the game the new folders saves (which will be created after starting the game) will also break.

If the game only stops working after adding CC and mods to it, you need to find which mods and CCs are broken according to the method given in the first post.
You can also read this topic:
https://answers.ea.com/t5/Technical-Issues-PC/FAQ-How-to-use-Mods-CC/td-p/8781409