As usual, the official Debian wiki has a great writeup on getting the Drivers installed. http://wiki.debian.org/NvidiaGraphicsDrivers. Do yourself a favor and read the document. It will give you the full story and not just the regurgitated short version below. I use debian because I like the packaging system. I think it works well. why add the agony of recompiling drivers whenever you update kernels and whatnot. Since X was broken, The key was to switch to a console session BEFORE logging in using GDM. As soon as the login page comes up, press CTRL+ALT+F2. This is what I had to be able to log in and use my X session:
Login as root.
I used the netinst disk and had to add the “non-free” and “contrib” repositories. to do this, edit /etc/apt/sources.list.
nano /etc/apt/sources.list
Find the line line that has something like
deb http://mirror.cc.columbia.edu/pub/linux/debian/debian/ lenny main
deb-src http://mirror.cc.columbia.edu/pub/linux/debian/debian/ lenny main
add “contrib non-free” to the end of both of these lines and then do a “aptitude update”
# apt-get install module-assistant nvidia-kernel-common
# m-a auto-install nvidia-kernel${VERSION}-source
# apt-get install nvidia-glx${VERSION}
In the device section, add
Driver "nvidia"
Restart GDM (and subsequently X)
# invoke-rc.d gdm restart
Install The nvidia settings interface thingy if you want. This can also verify if the driver is actually running.
aptitude install nvidia-settings
In debian, the package doesn’t install a shortcut for some reason, so just launch it by typing “nvidia-settings” into the console.