Latest questions about "hidden and dangerous 2"

After the successful installation of Hidden & Dangerous 2, I can't run the game. Message: Wrong cd key, contact Illusion Softworks.

I can save missions as many times at the easiest difficulty levels, and 3 times per mission at the second most difficult. I would like to do the same with the hardest level, but can't.

I bought Hidden & Dangerous 2 and I installed it on my laptop but it says that the cd-key I entered is wrong when I try to play it. Is there anything I can do to get it to run?