Sometimes your key is valid, but the game fails to "read" it correctly. You can check your key in the Windows Registry: Press Win + R and type regedit .
If you have an old physical copy, you can sometimes activate the key on Steam by providing proof of ownership (like a photo of the manual/disc) to Steam Support . Recommended Action
If you previously owned the physical CD-ROM version of the game, you do not need a generator.
A: 100% scams. They drive views to malware links. Comments praising the video are bots. Report them.
Key code generators for (2007) are almost exclusively malware or scams in 2021. 🛡️ The Reality of Code Generators
Purchase Call of Duty 4: Modern Warfare directly through Steam. Steam automatically embeds a unique, valid CD key into your registry, allowing seamless multiplayer access.