Alienware m17x R4 - Problems with my Nvidia 660m

I recently order an Alienware m17x R4 The specs :

Intel i7 3610 2.3ghz / 6gb ram / AMD 7970

The pc did not recognize the AMD card at all... I tried to got to a thecnitian but the AMD card it's not working and the pc never detect it. I'm in Dominican Republic and so hard for me to send the laptop to Dell in US... A partner gifts me a NVIDIA Card the GTX 660m...  My pc detect the card correctly but is not working. I run the 3dmark 10 and the integrated Card score higher than my discrete card. I tried to just use the discrete card pressing fn + f7 and when the pc boot and request me to enter the password after that, the screen turns just black and the pc reboot. After that the pc do the same just reboot and reboot after the black screen.

I remove the graphics card opening my m17x and place it again... After that I was able to use the laptop but with the same problem... avaliable to use just the Intel Graphics card... I trid to uninstall the drivers and reinstall it again (320.18 version ) and after reboot, press the fn + f7 again to switch, but I have the same problem... My nvidia GPU isn't working even the pc detect the card correctly.

 I update the Bios to A11, but the same thing is happening..