How to Change the Call of Duty 4 CD Keyby Chappy SinclairUpdated September 22, 2017
As with most PC games, you're required to input a CD key during installation. However, at some point, you may need to change the CD key. The most common remedy is to re-install. Unfortunately, Call of Duty 4 is a large game. Reinstalling is usually not ideal and very time consuming for frequent users.
Go to the main menu. Select "Options."
Locate and click on "Multiplayer Options."
On the Multiplayer Options screen, you will see another option that says "Enter CD Key." Copy the valid key directly into the text box. Do not include any special characters.
Click "Validate." You may need to restart Call of Duty 4 to update the CD key settings.
Changing your CD Key will delete the stats attached to the previous key.