ok, please try the following steps:
sudo apt-get --purge remove nvidia-331-updates nvidia-331
sudo apt-get install nvidia-331 nvidia-prime
sudo prime-select nvidia
Then reboot and you should be all set.
ok, please try the following steps:
sudo apt-get --purge remove nvidia-331-updates nvidia-331
sudo apt-get install nvidia-331 nvidia-prime
sudo prime-select nvidia
Then reboot and you should be all set.