Try this if you are getting to the menu list at boot (if not hit shift after the BIOS screen).

Highlight the kernel you want, hit 'e' to edit, find the line that ends with 'quiet splash' or either of those words, after a space add 'nomodset', follow instruction at bottom of page to save changes at boot.

This won't fix your problem but might get you in so you can have a better chance of a fix with a normally operating system. That change will also be lost on reboot.