"Your product key is invalid" error message when you start Halo: Combat Evolved

When you try to start Microsoft Halo: Combat Evolved, you may receive the following error message: This dialog box offers to link you to more information at: This dialog box has a check box that you can select to prevent the error message from appearing again.

Halo: Combat Evolved detects that the Product Key that is stored in the registry is missing or is damaged. This does not indicate that your Product Key is in use by someone else or has been stolen.

To resolve this problem, follow these steps:

1. Restart the computer.
2. Remove and then reinstall the game.
   
   Do not select the option to remove the saved game files because they are not part of this problem.
3. Try to log on as a different user.

When you receive an error message that is permanently dismissible, and then select to dismiss the error message, the information is stored in your registry as a binary value entry under the following registry subkey: Each error message is tied to your video card or your sound card regardless if it is a sound card problem or a video card-specific problem. This means that the binary value entry is named something that is similar to the following: The data in this value is a ‘y’ followed by 0 or 1 depending on if you click to select the option to show the dialog box again, and if you click Continue or click Continue in Safe Mode.

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:

If you click to select the check box to prevent this error message from being appearing again, you may miss this error message in the future. To view dismissed error messages, follow these steps:

1. Quit Halo: Combat Evolved.
2. Start Registry Editor.
3. Locate and then click the following key in the registry:
   HKEY_CURRENT_USER\Software\Microsoft\Microsoft Games\Halo
4. Right-click each binary value entry, and then click Delete.
5. Quit Registry Editor.