Please try the steps in the order below:
- Manually uninstall Origin
- Run CCleaner
- Restart your router/modem and do a Clean Boot
- Make sure that your UAC is enabled and set to notify
- Download the latest version of Origin and install the client - make sure to run the setup file with Admin rights
- Add firewall/antivirus exceptions for Origin and open the needed ports
- When starting Origin, please make sure to run it as Administrator
After these steps, right click the Sims 4 game tile in Origin client and select 'Repair Game' or 'Check for Updates'.