I've answered in that other thread.
If you're using Mandrake, you should be editing /etc/modules, not modules.conf.
The correct alias is (if you insist on editing modules.conf...) not char-major-195, though. Since Mandrake uses devfs, the alias should be /dev/nvidia*, as paleq said.
The reason it's char-major is that you probably ran the installer in failsafe mode. Is this right? If so, then Mandrake does not mount devfs in failsafe mode, so the installer couldn't detect which alias you need correctly.
The correct way to stop the X server is to run /sbin/init 3 as root from a terminal (ctrl-alt-f1 and log in as root).