When nvidia driver update make a mess of your Ubuntu ...

I have to face this issue after i update my nvidia graphics card driver in my Dell xps L502 which set the resolution of the display to 640X480 with 4:3 ratio.

I have tried almost all the things that could find in google but nothing work for me other than removing all the nvidia drivers, which include "nvidia current" and others.

After removing all nvidia drivers it still did not fixed the issue.

So i rename the xorg.conf in "/etc/X11" directory and then it worked for me.

PS: before doing that i also followed the instructions in below post also.

http://askubuntu.com/questions/127851/change-boot-screen-resolution

1. 
   We will have to edit grub configuration. Open a terminal and paste this:
   sudo gedit /etc/default/grub
   Hit Enter. It will open grub preferences in Gedit.
2. Locate the line "# GRUB_GFXMODE=800x600" (resolution may be different).

You have to change the resolution to actual resolution of your screen, for example mine is 1240x1024. Next step is to uncomment this line (remove the # and and the empty space if is, so the letter G of the word GRUB will be the first letter in this line). After u r done, save the file and close.

3 . Now paste this line in terminal:

sudo gedit /etc/grub.d/00_header .

Hit Enter. It will open a text file with a lot of stuff. Use the search option at the top of the window to locate this line:

gfxmode=${GRUB_GFXMODE} 

After u successfully find it, u will have to add this line: "set gfxpayload=keep" (of course without the " sign) just under the gfxmode=${GRUB_GFXMODE}. Make it look like this:

set gfxmode=${GRUB_GFXMODE}
set gfxpayload=keep

Now, save the file and close.

4 . In terminal paste:

sudo update-grub 

Hit enter, it will generate new grub.cfg file so the changes u made will be saved.

Reboot and enjoy your new boot screen resolution.

In case u don't know what is your screen resolution

Go to System settings - Displays