Lou22Eva Please clear the EA App's cache:
https://help.ea.com/en-us/help/faq/clear-cache-to-fix-problems-with-your-games/
and repair the game (EA App > Sims 4 > Manage > Repair). Then open the EA App as an admin: right-click the desktop shortcut and select "Run as administrator." Try to launch Sims 4 from within the App.
If that doesn't help, please uninstall the EA App with Revo Uninstaller (the free version is fine). Use the Advanced scanning method when asked. Restart your computer, download a fresh copy of the App installer, and run it as an admin. Open the App itself as an admin too, once it's installed.