Hi, when it stops? If grub2 starts try to boot the system in runlevel 3 (no graphic system): press the ‘e’ before it try to boot, than add a ‘3’ at the end of the line that start with “linux”. Press Ctrl + x to boot the system. If the system is ok it will boot and stop on a black windows with a prompt for login. If you can reach that point we can try to solve the problem.
If you fell into a recently seen problem after a kernel upgrade which shows as a kernel error on a black screen, try pressing CTRL-ALT-F2 then CTRL-ALT-F1 to get back to the desktop, then if network works, do a system upgrade and reboot.