Mine

tiina@tiina-desktop:~$ sudo nvidia-glx-config enable

Error: your X configuration has been altered.
This script cannot proceed automatically. If you believe that this
not correct, you can update the md5sum entry executing the following
command:
md5sum /etc/X11/xorg.conf | sudo tee /var/lib/x11/xorg.conf.md5sum
otherwise edit manually /etc/X11/xorg.conf to change the Driver section
from nv to nvidia.