Can't play it, ROe have a key, bott Doom 3 keep asking for it. Any solution?

Edit:
I found it. Through Gog.com website you can see your serial key for the game!

Thanks for the info. I had to ask other players if they had the same issue, they said website

for me the ROE key is missing and the last two digits are missing for Doom 3

About these CD keys, is there a limited number of uses for them?

No

Phew, that's a relief ! Thank you for your answer !

I can also attest to this since I used my Steam version's CD keys on the GOG version after having used them already multiple times and the Steam keys can also work even in the retail and GOG releases.

Good to know, thanks!

Where on the website is the CD key??? Still can't find it...

I'm also having trouble finding the CD key, either on the website or in Galaxy. Any solution?

It's one the website. Go to DOOM 3 in your GOG library on the website, click the More drop-down menu and you should see an option for Serial Keys, click that to reveal your CD keys for Doom 3 and Resurrection of Evil. Honestly I wish CD keys can be viewed on GOG Galaxy as well, it would save people the annoyance of having opening an internet browser to find it. I would also recommend backing up your personal doomkey and xpkey files to avoid having to look for it on the site again if you need to reinstall the game or something.

The digital releases of Doom 3 on Steam and GOG have a very stupid way of handling inserting CD keys. If you run into the situation where only one was inserted and not the other, for example RoE's CD key was registered but not base Doom 3 upon launch. Some users suggest launching into RoE first from the client and registering base Doom 3's CD key afterwards that way. I tried this method but strangely it seems to work with either game, I only need to register base Doom 3's CD key and the game accepted it, same for when I recreated Doom 3 having it's key pre-inserted but not RoE's. If you ran into both games have their respective fields are completely empty, then you have to enter BOTH CD keys together on that screen regardless of the game, registering only one set of CD keys will cause the game to complain the other didn't validate the missing CD key for the other game. It's also important to not that when entering the CD keys, they are NOT case sensitive from my testing but you need to make sure enter final two characters in the CD key at the appropriate field since originally the game's installer from the original discs had the keys being registered during installation in this 18-character alpha-numeric format with four characters divided by four dashes followed by the last two digits:

####-####-####-####-##

When registering your Doom 3 or Resurrection of Evil CD keys in-game, it is in this format instead where one string holds 16 out of the 18 characters and the last 2 characters in another in the same field (press Tab to switch between different fields):

################ ##

If you're still having issues trying to fill out your CD keys in-game, try deleting any files with the keyword key in the filename from either base and d3xp folders and then try again. Alternatively, you can try to create a blank doomkey and xpkey by creating a blank text file with no file extensions but in this format in ALL CAPS with NO spaces in between each character:

##################

I hope this might anyone out with getting the game to accept their CD keys.

Thanks for the info. Big help

I seem to remember having CD key issues with my disc version of Doom and RoE. If I recall correctly when I installed both of them which I usually did, after installation I had to start RoE first before I could start Doom 3 or I couldn't get the CD keys for Doom to take. id never did patch a fix for that .

I now find it ironic that once again we have a CD key related issue , LOL, with this much appreciated original verson. BFG was Ok becuase it's marine was smarter than original Doom marine becuase he had MacGyvered a flashlite that could stay on with weapon out but BFG just isn't the same game as the original afaic

Many thanks! That did it.

Guys, after you added your cd-keys for D3 and RoE you should go to the installation folder of the game and find doomkey and xpkey and make them "read only". The game will never ask key anymore.