I have a Asus Notebook (X450L) with Ubuntu 14.04, it has a nvidia card 720m and a Intel HD Video onboard. All working just fine until yesterday, when I updated the system.
Now, after the login screen, I've got a screen stucked like that:

I've tried all that is on this topic: Ubuntu Desktop does not load , but none of that really works for me :(
I've also tried to reinstall lightdm and, after that, dpkg-reconfigure lightdm.
Obviously, I've tried too removing all nvidia driver and reinstalling them... nothing works... I'm really upset with this, can somebody help me?
Thanks in advance