Buy Now Banner locking up game

@illyana_magik  Try playing in windowed mode.  Go into Documents > Electronic Arts > The Sims 4, open Options.ini, search for fullscreen , and set it to o (zero).

If this doesn't help, restart your computer, and before opening Sims 4, go through the Task Manager and shut down any app that doesn't need to be running, for example Steam or Discord might still be active.  Check the background processes list too.  And go into the EA App and disable its in-game overlay, which is under Settings > Application.

In the future, you should be able to use ctrl-alt-delete to choose to log out rather than bring up the Task Manager.  This will boot you to the login screen rather than forcing you to restart.