Remembered that I had the CD for Half-Life and learned you can put the CD key in to unlock it. Was surprised that I also unlocked the add-ons with this version. :
Steam Community :: Guide :: Steam: How to activate CD Game Key.
How to Activate Third Party Game Codes in Steam
How to activate cd keys on Steam. - AllKeyShop.com
How to activate cd keys on Steam. - AllKeyShop.com
How to redeem Steam keys and codes on mobile and in app | Pocket Gamer
![How to Find Steam Game Serial Key or CD Key? [2 Solutions]](https://www.easeus.com/images/en/screenshot/todo-pctrans/steam-cd-key.png "How to Find Steam Game Serial Key or CD Key? [2 Solutions]")
How to Find Steam Game Serial Key or CD Key? [2 Solutions]
How to activate CD key on Steam? A simple tutorial on GG.deals
How to Add Steam Key to Steam and Install Game - Activate Game - YouTube
Steam now allows activation of game keys from web browser
How to view CD key for a Steam game? - Arqade
How to redeem Steam keys and codes on mobile and in app | Pocket Gamer
Example screenshots for Steam CD Keys - Salad Support
How to Activate Third Party Game Codes in Steam
How To Redeem A Code On Steam - Unlock A Game - YouTube
/cdn.vox-cdn.com/uploads/chorus_asset/file/23268543/b.jpg "How to redeem a Steam key on Steam Deck - Polygon")
How to redeem a Steam key on Steam Deck - Polygon
How to activate cd keys on Steam. - AllKeyShop.com
How to activate cd keys on Steam. - AllKeyShop.com
Steam Support :: Steam-Issued Activation Keys
How to Use Steam Keys: 12 Steps (with Pictures) - wikiHow
/cdn.vox-cdn.com/uploads/chorus_asset/file/23268326/cplante_220223_ecl1072_0027.jpg "How to redeem a Steam key on Steam Deck - Polygon")
How to redeem a Steam key on Steam Deck - Polygon
Tutorial: How to activate a game cd-key on Steam - YouTube
