Uninstalling TS3

Hi,

I've recently been having some issues with The Sims 3. About two weeks ago, I decided to temporally uninstall The Sims 4, to have enough space on my computer to install TS3. Previously I've only played TS3 on my old PC, but they were played via Origin, so TS3 were already listed under My Games. All I had to do was to uninstall TS4 and install TS3, which I kinda figured out how to do myself and everything went by smoothly.

 When I later tried to play the game, everything was going great until about 20 minutes in, when the game crashed. So I delete whatever CC I'd already installed and restarted the game, but the exact same thing happened again. I try over and over again, but it never works past 20 minutes.

I still didn't know what the problem was, but eventually I gave up and figured I'd go back to TS4 again. Before, when I was uninstalling TS4, there had been an option when right-clicking on the game to uninstall (amongst a bunch of other options as well). But when I now tried on TS3, the only option that appeared when right-clicking was play.

Since then, I've tried multiple different tutorials on google and youtube, but all I can find either uses the right-clicking or the uninstaller, which btw I have no idea how it works. I've also searched through most of the questions and answers on different websites, including this one, but never found anyone seeming to have the same problem as me.

Maybe it's just some sort of bug? Or maybe I did something wrong while installing it? I don't know or understand any of this stuff, but I would highly appreciate if anyone knew a solution to this problem.

Thanks in advance.