Have problems with Assassin's Creed no cd crack!

[Belgiangeneral]

Hi there, first post and thread I need your help.

Here it goes.
I bought Assassin's Creed for PC. I put the cd in my computer. The install menu showed up. I clicked "install". It installed succesfully. However, if I then launch the game (or press "play") it says "Please insert the correct cd-rom, select OK and restart the application." This is simply bullshit And yes, it was installed in the correct drive.

I asked some friends what to do. They said "go to gamecopyworld and download a no-cd crack".
So I went to gamecopyworld (didn't know if it's existence beforehand) and downloaded the assassin's creed no cd crack. It was a 7z file. So I opened winrar, selected the file and clicked "extract to". I got this error : "No archives found in selected files and folders".

What did I do wrong???
Thanks for your help in advance