Websites using phrases like "ghostbusters-the-video-game-free-download-pc-game-full-version" are often and can be high-risk for malware or viruses. For a safe experience, it is recommended to stick to verified retailers like Steam or Epic Games.
If you are looking for on PC, there is no official "free" version available for permanent download. While the Remastered version was offered for free on the Epic Games Store for a limited time in 2020, it is currently a paid title available on major digital storefronts. Where to Get the Game
The 2009 version is often requested by the community here, but not currently for sale. PC System Requirements (Remastered)