If like me, you one day turn on your machine and get nothing but a black screen and start crying like a kid who’s dropped their icecream, fear not. You can reset your your graphics mode via the grub boot loader on boot.
1. While booting hold down the “SHIFT” key until the grub menu loads
2. Hit “e” on the bootloader option for your ubuntu install. This display the grub editor.
3. Change “quite splash” to “nomodeset” without the quotes.
4. Hit “CTRL”+”x” to boot
Done. This should reset your graphics options. You can than use System -> Administration -> Additional Drivers to install the latest drivers.