Changing Chaos Theory Multiplayer DVD key

[zawaia]

Hi guys,

I tried SCCT from a friend a few months ago. Even tried the multiplayer. After, I uninstalled the game but keep the saved files. Now I just buyed the game and I would like to play in multiplayer against or in coop mode with my friend. The problem is that it seems the game still uses the CD key from his DVD, and don't even asks for my key. So each time we try to play at the same time, me or he receives the message that there's someone else already playing with the same key. How do I force the game to asks me for the new key. Is there a place from where I can delete the old one, in the registry or some file?
Thanks in advance.
Regards,
Zawaia
Brussels