The Steam "Complete Edition" version has Steamworks integration , meaning you no longer need the defunct Games for Windows Live software to play.
Look for the "Live Access Code" in your physical manual. DiRT 3 Complete Edition Free Download
These videos showcase the gameplay of the Complete Edition and provide visual guides for the Steam activation process: DiRT 3 Complete Edition Free Download
Getting a copy of DiRT 3 Complete Edition is no longer possible through official storefronts like Steam or Humble Bundle, as it was delisted in early 2017 due to expiring car licenses. DiRT 3 Complete Edition Free Download
Subreddits like r/abandonware often maintain links to older delisted titles. Technical Tips