3.8 kernel in 12.04
sudo apt-get purge linux-image- linux-headers- sudo apt-get install linux-image-generic-lts-raring linux-headers-generic-lts-raring
sudo apt-get install --install-recommends linux-generic-lts-raring xserver-xorg-lts-raring libgl1-mesa-glx-lts-raring
sudo purge nvidia* sudo apt-get install nvidia-current sudo reboot