Nvidia driver activated but currently not in use
I've just installed Ubuntu on a new machine and it work perfectly except for the NVidia Graphics driver. When booting from the USB everything worked fine but Ubuntu sent me to the "classic" interface when I booted for the first time.
I installed Unity 2D but it's really not the same thing. Now even when I log on with the Ubuntu interface selected (Unity 3D) Ubuntu logs on with the 2D interface.
I checked the "additional drivers" tool and it tells me that the driver is "activated but not in use"
What can I do to resolve the problem?
Update: here's a screenshot of the "additional drivers" utility