Kohan 2 wouldn't run for me at first, so I tried the same thing I did for GTA3, Vice City, and Hitman 2. I disable the DEP (Data Excecution Prevention) for the game. You do not have to disable it completely.
To do this:
Right click My Computer.
Select Properties
Select Advanced system Settings on the left side
Go to the Advanced tab, and then the Performance section on top, click Settings
go to the Data Excecution Prevention tab.
click the second option and add the Kohan 2 exe (k2.exe) to the list
(restart PC if necessary)