Lets start from scratch and see ...
First remove everything related to nvidia
Then add the X - Swat PPA , it has the 304.64 driver and install the driver, and if I'm correct is the latest (newer) driver that supports Nvidia 6200.
sudo apt-get remove --purge nvidia-*
sudo rm /etc/X11/xorg.conf
The dist-upgrade command needed here in case new driver needs some upgraded libraries.
sudo add-apt-repository ppa:ubuntu-x-swat/x-updates
sudo apt-get update ; sudo apt-get dist-upgrade
sudo apt-get install nvidia-current nvidia-settings
Reboot and see the results.
If not work , give again the results of