If u get only black screen than try it.first start your ubuntu in nomodoset
here is solution open this link and follow step
My computer boots to a black screen, what options do I have to fix it?
here is simple step:-
when the grub menu appear press 'e' to edit button
then find quiet splash and delete this quiet splash
and type nomodeset and than press ctrl+x
you can install your graphics driver
but remeber your screen resoultion set 800x600
but dnt worry after your system reboot u can access your ubuntu in 800x600 resolution...
open your terminal and type
sudo add-apt-repository ppa:bumblebee/stable
sudo add-age-repository ppa:ubuntu-x-swat/x-updates
sudo apt-get install bumblebee bumblebee-nvidia linux-headers-generic