LinuxQuestions.org - [SOLVED] Ubuntu update- now i cannot log in to desktop

hello

I clicked on an ubuntu update from update manager, but now i cannot boot to my desktop.(i am at present on a live cd to talk to you guys)

when i boot, i go to grub then select a kernel and i am taken to a black page with a login and then after login, a command line.

I tried to reinstall nvidia drivers, but no luck, I may not have done it right though. I did try to remove them and reinstall but I do not know if i chose the right ones :?

at the command line, i type ' startx '

i get messages like this:

"FATAL: Errror inserting nvidia_304 (lib/modules/3.12.0-32-generic/updates/kdms/nvidia_304.ko) : unknown symbol in module, or unknown parameter (see dmesg)

fatal server error
no screens found

unable to connect to xserver no such file directory.
server error"

when i try this:
sudo cp /etc/X11/xorg.conf /etc/X11/xorg.bckup
sudo cp /etc/X11/xorg.conf.failsafe /etc/X11/xorg.conf

It says no such file or directory. there does not seem to be an xorg.conf or .failsafe file availible either

I have tried to boot with failsafe graphics from the grub menu, but no joy. if i choose a recovery mode option > resume normal boot , on any of the kernels, i am taken again to the black screen username-system-product-name login , when i log in, it again becomes a command line. ; /

and i have tried previous ubuntu versions from the grub menu too but they all take me to the command line also. so maybe its a disply problem?.

the live cd works fine, so my computer is o.k

i have files on my desktop and in my home folder that i really need to keep.

please can someone help me, i have no idea what has happened.

Thank you : )

i am on ubuntu 12.04.4, I was using gnome desktop (not unity)

quad p4 q6600
1066mhz 2 gig
asus p5q delux
7200 gs geforce graphics ( comand line 'lspci' this card is displayed as a vga compatible controller )