EA isn't working

OxyMediaGaming  Did you try the other suggestions?  Please do if you haven't already.

If those don't or didn't help, try manually uninstalling and reinstalling your 2015 and newer VC++ runtimes.  Click Windows key-i, select Apps, scroll down to the Microsoft Visual C++ Redistributables, click on any version from 2015 or later, and select Uninstall.  Don't touch the older versions.  You can download the newest runtimes directly from Microsoft:

https://docs.microsoft.com/en-US/cpp/windows/latest-supported-vc-redist?view=msvc-170

You'll need both the x86 and x64 versions of the 2015-2022 runtimes, but you can skip the ARM version, which is for a different class of device.  Restart your computer after installing and before trying to play.

If this doesn't help either, do the same for the 2005 x86 runtime.  It won't say x86 in the list of apps, but it's the correct version as long as it does NOT say x64.  You can get a fresh copy here:

https://www.microsoft.com/en-us/download/details.aspx?id=26347

You only need to install the x86 version, not either of the others.

While you're trying to install Sims 3, open the EA App as an admin each time: right-click the shortcut and select "Run as administrator."