This manual on steam or is it a paperback manual?

PCGamingWiki doesn't know that game, but google suggests that it is a compilation of Valve games published by Sierra. Thus, the easiest guess is that the key simply doesn't work on Steam.

Half-Life: Generation
Release date
1999 (original edition)
November 30, 2000 (Counter-Strike edition)[1]
March 22, 2002 (Blue Shift edition]


Thats a very old, non-US Half Life compilation. Even if that key hadnt been used in 20+ years, those keys became invalid on Steam years ago if I remember right.

I had Half Life Generation back in the day and it's a physical boxset of the original, Opposing Force and Blue Shift trilogy. This is a pre-Steam package too so the CD key is nothing more than the code required to install the game from the disc on your hard drive. It cannot be used to add the game to your Steam account.

If you are interested in these games then the collection is literally at a bargain bin price as it is in this sale https://psteamproxy.yuanyoumao.com/bundle/231/HalfLife_Complete/

引用自 J4MESOX4D：

I had Half Life Generation back in the day and it's a physical boxset of the original, Opposing Force and Blue Shift trilogy. This is a pre-Steam package too so the CD key is nothing more than the code required to install the game from the disc on your hard drive. It cannot be used to add the game to your Steam account.

If you are interested in these games then the collection is literally at a bargain bin price as it is in this sale https://psteamproxy.yuanyoumao.com/bundle/231/HalfLife_Complete/

oh ok thanks

引用自 AmsterdamHeavy：

Half-Life: Generation
Release date
1999 (original edition)
November 30, 2000 (Counter-Strike edition)[1]
March 22, 2002 (Blue Shift edition]


Thats a very old, non-US Half Life compilation. Even if that key hadnt been used in 20+ years, those keys became invalid on Steam years ago if I remember right.

oh ok thanks

One possibility is that the CD key you are using is incorrect or has already been used. Make sure you are entering the key correctly and that it has not already been activated on another Steam account.

Another possibility is that there is an issue with the game itself or the way it was installed. Try uninstalling and reinstalling the game to see if this fixes the problem.

If you have tried these things and are still having trouble activating your game, you may want to try contacting Steam support for further assistance. They should be able to help you troubleshoot the issue and get your game working.

引用自 Ashpex°彡：

One possibility is that the CD key you are using is incorrect or has already been used. Make sure you are entering the key correctly and that it has not already been activated on another Steam account.

Another possibility is that there is an issue with the game itself or the way it was installed. Try uninstalling and reinstalling the game to see if this fixes the problem.

If you have tried these things and are still having trouble activating your game, you may want to try contacting Steam support for further assistance. They should be able to help you troubleshoot the issue and get your game working.

We've already established that the game is a non-Steam product and the key is an installation one for the disc.

The game keys that were allowed was changed over 10 years ago. Which is why original Sierra keys no longer work.