can Alienware M17x R2 support Nvidia video card ?

 I have  a  alienware M15x  with Gtx 260m  and  M17x R2  with   Hd5870m single card  ,    Ati 5870m  is a powerful video card , however , it does not have Physics  processor  as Gtx 260m ., I want to play  a game with physics  on my M17x R2 , so I think it s better to install  the Gtx 260m on it . I pull Gtx 260m from M15x ,and  replace the 5870m  on m17xR2 with Gtx 260m . I download the gtx260m driver for m15x .However ,  the  driver  can not be  installed . whatever way  I tried install it in , it always appears to be  " standard Vga graphics adapter "  in the device manager .  I then update the Bios from A05 to A06 for 17x R2 ,but  still the same problem .I  have tried  formatting the disk and  reintalling the windows  7 .,  not recognize Nvidia  graphic card . I have tried searching the nvidia driver folder and open the  INF file to select the correct model to install . .Having no choice , I tried  removing the harddrive on m17x R2 and  just replace the harddrive on m15x ( since M15x and m17x R2 have almost the same chips on the motherbord ,both are intel pm55). To my surprise ,  Nvidia  Gtx260m is recognized on my M15x  with the harddrive from M17x R2  !. How come ?    can it  say that  M17x R2  does not support Nvidia  graphic card anymore ?