Right click on desktop >> choose Nvidia Control Panel
>> under 3D Setting >> Manage 3D Settings
Under TAB Global Settings >> select from drop menu "High-performance NVIDIA processor"
NOW select TAB Program Settings
Under 1.select a program to customize >> drop menu & browse game exe >> press Add
Under 2.select the prefered graphic processor >> drop menu & select "Use global setting (High performance Nvidia processor)"
Now try & enjoy the game
I had the problem on my Laptop with Win 7 & it worked