Install SIMS 3 via Origin without registration code

Where do you get the message ? When trying to activate on Origin or on installing on the blue window with the sims ?

For Origin

You don't need to re-register again. Simply login with your Origin account

Installation window

Get in touch with a customer support game advisor

Game advisors can be found through live chat.

1. https://help.ea.com/en/contact-us/ 
2. Click on the orange NEXT button
3. Select a platform
4. Click on the orange NEXT button
5. Select a topic and describe your problem in a few words
6. Click on the orange NEXT button
7. Click Chat Now to chat with a Game Advisor
   

In Details here: How to contact a Game Advisor using the new EA Help page