Activate the game through CD-Key - Quake 4 - Steam Community

: Most original 2005 DVD/CD releases require the serial code for both installation and multiplayer access. Steam Version

: While the Steam version typically installs the key automatically, you can find it by right-clicking the game in your library and selecting "View CD key" GOG Version : The digital

For many gamers, that "Serial Code" was the most important piece of paper in the house. If you lost it, you lost the game. How Quake 4 Used Serial Codes

As a product, the CD-key was a necessary hurdle. It was a standard security measure for its time. Today, buying a "Serial Code Quake 4 CD-key" is usually a trip down memory lane or a way to get a legitimate copy running on a retro PC build.