@LOL44l The antivirus could still be a problem, so please do try disabling it if you haven't already and you use a third-party program. If you only use Windows Defender, find out whether Controlled Folder Access is enabled, and if so, either disable it or set exceptions for TS3.exe and EADesktop.exe. This guide was written for Sims 4, but the relevant settings are the same:
https://crinrict.com/blog/2019/03/windows-10-defender-controlled-folder-access.html
If that doesn't help, please do a clean uninstall of Sims 3 and the EA App with Revo Uninstaller. Start with Sims 3:
- Download Revo Uninstaller (the free version is fine) from here.
- Launch Revo, select Sims 3 from the list, and click Uninstall.
- Once the game is uninstalled, select "Moderate" under "scanning modes," and click Scan.
- Review the list, in case there's something you want to save; otherwise, click Select All, and then Delete.
- Close Revo, and restart your computer.
I don't have instructions for uninstalling the EA App at the moment, but it should be straightforward. Restart your computer, install the App, and create a new folder into which you'll be installing Sims 3. The folder should be on the root level of the drive of your choice, e.g. C:\Games, not C:\Program Files\Games. When installing Sims 3, you'll be able to choose this folder.
If you do use a third-party antivirus, please disable it while installing the game, and try to play once before reenabling it. If this works, you can set exceptions for TS3.exe and EADesktop.exe. And if you use Controlled Folder Access, you may need to reapply the settings after reinstalling.