I'm probably a fringe case - people probably shouldn't take this advice over other advice posted widely across the internet.
I simply could NOT get Nvidia installed on my fresh install of sparky. Things are rather screwy here - I have TWO graphics cards on my system.
root@awesome:/home/guy# inxi -G
Graphics: Card-1: Advanced Micro Devices [AMD/ATI] ES1000
Card-2: NVIDIA GK208 [GeForce GT 630 Rev. 2]
Display Server: X.org 1.17.1 driver: nvidia
tty size: 80x25 Advanced Data: N/A for root
You may well ask, "Why do you have TWO video devices, one from each major brand?" Well, I've got a server board, with an onboard ATI graphics controller, plus the GT 630 installed into the PCIe slot.
root@awesome:/home/guy# inxi -M
Machine: Mobo: Supermicro model: H8DM8-2 v: 1234567890 serial: 1234567890
Bios: American Megatrends v: 080014 date: 10/22/2009
Pavroo's DDM failed me, as did a dozen other guides posted in various places. Each and every time I would get my Nvidia driver installed, I would reboot to a hung screen. There is no place in the Bios to simply disable that stupid emasculated ATI card. There is no option to use PCIe first, or exclusively, or anything like that. I've got the ATI, and that's that, end of story. If I'm to get my Nvidia working, I've got to somehow work around the ATI.
This is what finally worked for me. I followed this particular guide, which doesn't seem to be greatly different from several other guides available, with TWO modifications.
First, I blacklisted the nouveau modeset in grub, according to this page http://www.linuxquestions.org/questions/fedora-35/how-to-permanently-blacklist-nouveau-module-in-fedora-17-grub2-4175437409/
GRUB_CMDLINE_LINUX="rd.md=0 rd.lvm=0 rd.dm=0 SYSFONT=True KEYTABLE=us rd.luks=0 LANG=en_US.UTF-8 rhgb quiet rdblacklist=nouveau"
grub2-mkconfig -o /boot/grub2/grub.cfg
THEN, I blacklisted the Nouveau driver in /etc/modprobe.d/blacklist-nouveau.conf
options nouveau modeset=0
alias nouveau off
alias lbm-nouveau of
Once I had Jessie's current Nvidia driver installed, I rebooted, and joy, joy, joy - I went straight to the graphical login screen!
Not quite content, I decided to switch over to the experimental branch, to see just which driver I might install. This is my modified sources.list, with appropriate comment lines.
deb http://ftp.debian.org/debian/ testing main contrib non-free
deb-src http://ftp.debian.org/debian/ testing main contrib non-free
deb http://security.debian.org/ testing/updates main contrib non-free
deb-src http://security.debian.org/ testing/updates main contrib non-free
deb http://www.deb-multimedia.org testing main non-free
## Other repos can be found in /etc/apt/sources.list.d directory ##
## used only to install NVIDIA 346 driver
## may be used again if I find it desirable to update NVIDIA
## deb http://ftp.debian.org/debian/ experimental main contrib non-free
## deb-src http://ftp.debian.org/debian/ experimental main contrib non-free
Reboot, and I'm good with my Enlightenment desktop!
Final step to get the system I'm looking for, is to install the Liquorix kernel. Be back in a few minutes to report on that . . .