Since you have an Nvidia card, installing the proprietary driver may provide better support.
Open a terminal, and run these commands:
Then restart your machine.
sudo apt-get install nvidia-current
The worst case scenario is that you boot into a black screen. Avoid pressing your power button to restart or power down your machine. Instead, you can get into a text-mode console by pressing Ctrl+Alt+F1 (or F2). You can login there using your regular user. There you can restart by running:
and turn it off by running:
In any case, booting into a black screen using the Nvidia driver may indicate that your card does not support the kernel mode. To allow compatibility set the flag 'nomodeset' on the grub options.
While in text mode, edit this file:
Look for a like that looks like this:
sudo nano /etc/defualt/grub
Add nomodeset to it so it looks like this:
Save the file, and reboot.
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash nomodeset"
Hope it helps. Let us know how it goes.