November 2020 - last edited November 2020
Ok, so what I just did now was finding each Sims 3-related files and deleted them one by one. When I right-clicked on these files, there was no 'uninstall' option, that's why I clicked 'delete'. Then I emptied the trash bin and ran CCleaner afterwards. Note that the search bar of CCleaner, just as Revo, couldn't pick anything while I typed 'Sims' or 'TS3'. Then I uninstalled Revo and CCleaner and downloaded them again -same thing again.
In absence of Sims related-files showing up, is it reasonable to think that Sims 3 is wiped off for good? Is it safe giving a try to reinstall the game now?
November 2020
@SierraLeone4 I can't be sure without seeing your computer, but what I suspect is that the registry entries for Sims 3 were wiped and not restored, and that's why the game has been showing as not installed even with all the program files present. If that's the case, then yes, you should be able to reinstall without any problems. The registry entries are what CCleaner and Revo are meant to remove, and leftover entries are what can prevent the game from launching after a reinstall.
Just to be safe though, please look at this guide to manually uninstalling and make sure you don't find any of the registry entries on the list.
https://sims3.crinrict.com/en/2011/01/tutorial-how-to-get-rid-of-unwanted-custom-content.html
It's a lot easier to remove them now than later. And to be honest, I'm not sure that your particular install would have exactly the same entries as a disc install, whcih is why I though it would be better to let CCleaner or Revo search. But you can look yourself for anything suspicious, especially anything with the name EA, Sims, or Origin in it. Since Sims 3 is a 32-bit app, you only have to look in the Wow6432Node section.
November 2020
November 2020
@SierraLeone4 You should be able to download and install the base game and expansion and stuff packs from Origin without needing to input a code again. Just open your Origin library, click on the Sims 3 icon, and then click the Install button. If Origin doesn't ask you whether you want to install all your packs as well, you can manually start those downloads once the base game is installed.
If you own any store worlds or other store items, you'll need to download those through the store itself. Go to store.thesims3.com, sign in with your Origin credentials, then click Store > My Store Account > Purchase History to view your owned items, or just download them directly from their product pages.
November 2020