This is the way I installed Carnivores 2 on my Windows 7 64x:
First install the game on any operating system Windows XP(32x) or earlier.
(If you don't have any other OS, install virtual machine. Click Here
Copy the installation files (C:/program files/carnivores 2) and copy them to you Windows 7 (C:/program files/carnivores 2)
Run the game! If you don't have sound, go to options and change the Audio Driver to Direct Sound 3D. Leave the Video Driver on Software.
This may work on Vista 64x OS's but I'm not sure. I do not own a Vista and I never will cause it sucks.
Hope this guide helps