And this suggestion is not the right way.
1st, sgfxi installs the driver by byppassing the package-management
2nd, usin /etc/X11/xorg.conf is depricated and should not be suggest.
apt-get install nvidia-kernel-dgms nvidia-glx + make the little config in /etc/X11/xorg.conf.d/20-nvidia.conf
where is the problem there?