Sims 3

@misjean92  When uninstalling, it's necessary to clean your computer's registry before trying to reinstall.  You can clean the registry manually, or with a tool like Piriform's CCleaner (free download).  Otherwise, those leftover entries can prevent you from installing or launching the game going forward, as you're seeing now.  It may also help to clear Origin's cache before reinstalling.

https://help.ea.com/en-us/help/faq/clear-cache-to-fix-problems-with-your-games/

Originally, the issue was probably that your save had become corrupted, or maybe you had a corrupt file in your game folder in Documents.  There was nothing wrong with your program files, and no reason to uninstall.  Compatibility mode was and is unnecessary as well—TS3 runs just fine in Windows 10.

I don't honestly know enough about computers to know how to do any of this. I hate how complicated simply playing a game has become, I never used to need to know more than installing and uninstalling, I've tired to delete possible corrupted files as well but it didn't work. I've tried your suggestions and continue your have the same problems

@misjean92  The corrupted files I referred to would be in your Sims 3 game folder in Documents\Electronic Arts, if you still have that folder.  (It may have been removed when you uninstalled.)  If it's there, you can drag it onto your desktop and leave it there until you're ready to sort through its contents, which wouldn't be until after you got the game running.

It sounds like you're not comfortable cleaning your computer's registry manually, and that's the safer approach—deleting the wrong file can cause your computer to stop working entirely.  But the nice thing about cleaner apps, at least the good ones, is that they'll remove the correct files for you without touching anything else.  I suggested Piriform's CCleaner because it's popular and works as intended, and there's a free version.

Whichever cleaner app you choose, uninstall the game and then just follow the app's instructions to remove all Sims 3-related files from your computer.  If you do still have a game folder in Documents, or on your desktop if you've moved it, be sure to rename the folder so it doesn't get deleted with everything else.

Once you've cleaned your computer, you can reinstall the base game to make sure it works, and then start adding your packs.