DOOM 64

If you do not have a Steam account, you will need to download the client from the official website, install it and then create your account. Once you are logged into your account, click on "Add game" in the bottom left corner and then on "Activate product on Steam". After a few clicks on "Next", you can finally enter your CD key, the game will automatically be added to your library and the download will begin.

More information on Steam

To activate your game with Epic Games, log in to your account on their website, click on "Redeem Code" at the top right of the page, and then enter the game's CD key or code in the field provided. Click "Redeem" to verify the code and add the game to your Epic Games game library. You should now be able to download and play the game from your library.

Learn more about Epic Games

Use your Microsoft Points game card on Xbox Live Marketplace on your Xbox Series X, Xbox One or Xbox 360 to buy full games, rent the latest movies in high definition and enhance your games with downloadable content. Unlock the full potential of Xbox Live! To access Xbox Live Marketplace, you will need the following components and services: an Xbox Series X, Xbox One or Xbox 360 console, a broadband internet connection, an Xbox Live Silver membership (included in Xbox entertainment content), a Microsoft account and an Xbox console hard drive or storage unit.

Use your code on the Xbox Live network to activate your games or increase your Xbox Live account's credit. To access the Xbox Live network, you need the Xbox One, a broadband connexion, a Xbox Live account, and a storage device according to your console: Hard disk drive, memory card, or USB drive.

Play Anywhere games can be played on your PC and your Xbox. You will need to have installed the Windows 10 Anniversary Edition update on your PC, as well as the latest update on your Xbox One console. You only have to log into your Xbox Live/Microsoft account and your Xbox Play Anywhere games will be available to download. On your Xbox One, games will show as "Ready to Install" under "My Games and Apps". On your Windows 10 PC, games will appear in "My Library."

To activate a game you download on GOG Galaxy, open the application on your computer, log in to your account, click on the menu icon, and then select "Game Codes". Enter the game code in the appropriate field and click "Continue". Once the code is verified, the game will automatically be added to your GOG Galaxy library where you can download and play it.

Learn more about GOG Galaxy.