-For anyone who has problem with CD key registration , I've come up with the fix.

-So, when you try to launch a game, a window with a message like this appears:
"Please enter your purchased CD key blah blah blah down below:"
XXXXXXXXXXXXXXXXXXXX%CDKEY_PART1%%CDKEY_PART2%%CDKEY_PART3%%CDKEY_PART4%%CDKEY_PART5%

-which the XXX part is a 20 letter code. All you have to do is to seperate these 20 codes in 5 parts of 4 letters and put them in the format given to you in the following text. So what you basically should enter in the slot will be something like this:
%XXXX%%XXXX%%XXXX%%XXXX%%XXXX%

-and A Voila, cheers and have fun!


Edit: Be Mindful!
Don't delete or modify the message in anyway the first time you launch the game! any changes you make will get saved to the registration message, and you will lose the code it gives you.
Maybe deleting and reinstalling the game would make the message pop up again but I haven't tried that and am unaware of.