Please check all your windows updates are installed.
To install updates go to Control Panel and click windows updates and click on check for updates
Install all important updates and restart the computer.
If you are facing issue with any particular browser try to download Mozilla Firefox and check it.
Install latest version of adobe flash player https://get.adobe.com/flashplayer/
If you are still facing an issue ,Try to create a new user account and check.Refer the link below
Hope these steps will help you to play your Facebook games again.