Don't use Nvidia X server settings, if there are no proprietary drivers (see: system>additional drivers). It won't work, only spoil the system if you try nvidia-xconfig as root. It will set screen resolution to 640*480.
After searching http://www.nvidia.com/object/linux-display-amd64-302.07-driver.html, http://bumblebee-project.org/ and some posts on http://askubuntu.com I resolved to stay within Ubuntu and typed following lines into terminal (to open terminal you can 'ctrl+alt+t'):
sudo apt-get purge nvidia-current
sudo apt-add-repository ppa:ubuntu-x-swat/x-updates
sudo apt-get update
sudo apt-get install nvidia-current
After first sudo you will need to enter password. It takes time between each of line to perform actions. After succesful exec exit terminal and restart OS. Now my screen looks fine and comp (Asus K55V with GEFORCE 610M, Ubuntu 12.04.1 LTS 64bit) works good. There still are no additional drivers.
I installed 'Stellarium', that uses opengl. It didn't start, because "no opengl"
Than I entered in the terminal following lines:
sudo add-apt-repository ppa:bumblebee/stable
sudo apt-get update && apt-get install bumblebee-nvidia
I suceeded only after 3-rd atempt becouse of server problems. First two attempts ended up with some "E:" lines.
After that 'stellarium' started sucessfuly.
I noticed, that nvidia-current is fitted for a defined kernel, so after update U need to repeat this all again. Shoul those lines be in some script?
And try this:
I noticed diference ~3 times. And yes, there still no additional drivers.