Changed from 460m to 675m in R3 and the graphic is not detected for the Alienware..help please!

Hi guys!

I have bought a gtx675m for my R3...and I just installed it...and I can see the desktop but with a 640 resolution and in devices there is a message like: vga un know
I'm trying to install the drivers for the 675 but any time I try to install it I receive a message like: there is no hardware for this software..

Please what can I do?? I'm desperate...and this important because I pay money and I need to know if this graphic is compatible or work in my R3!

thanks in advance!

(and...

Changed from 460m to 675m in R3 and the graphic is not detected for the Alienware..help please!