ALT+CTRL+F1
Then light mode:
sudo service lightdm stop
And the launch downloaded *.run file from NVIDIA
sudo reboot
Or hard mode:
sudo service lightdm stop
https://askubuntu.com/questions/841876/how-to-disable-nouveau-kernel-driver
sudo apt-get remove nvidia* && sudo apt autoremove
sudo nvidia-uninstall
sudo apt-get install dkms build-essential linux-headers-generic
sudo mcedit /etc/modprobe.d/blacklist.conf
>> Insert follow lines to the blacklist.conf:
blacklist nouveau
blacklist lbm-nouveau
options nouveau modeset=0
alias nouveau off
alias lbm-nouveau off
echo options nouveau modeset=0 | sudo tee -a /etc/modprobe.d/nouveau-kms.conf (may not exist,it is ok)
sudo update-initramfs -u
sudo reboot
And the launch downloaded *.run file from NVIDIA