lost product key

Hi I didn’t even know this site existed!!! Though its been a while since I have played… I have a Combat Evolved game which I bought in 2005 and played for 1000’s of hours in mulytiplayer after completing the game. My children have now discovered it and have been playing it until today when I upgraded the steam powered PC they were using. I cannot see the product key on the box or in the instruction book. Where do I need to look? I appreciate any help .

Winston aka “furball”

Try to search one on the Google.

Thanks CateredEagle ,I got sorted