Re: Sims 4 not launching

@fittergirly  Please download a fresh copy of the EA App installer and try to run it.  You'll likely see the option to repair rather than reinstall, and if so, choose that.

If that doesn't help, uninstall the EA App with Revo Uninstaller (the free version is fine), and restart your computer before reinstalling.

In either case, run Steam and the EA App as an admin: right-click each desktop shortcut and select "Run as administrator."  Make sure both are loaded properly before trying to launch Sims 4.