I haven’t seen the demo, and packages for NVIDIA video drivers are better supported under x86_64 Ubuntu versus Fedora, so some of what I know will differ slightly.
Yes, presence of Nouveau in any way will lead to the NVIDIA driver not loading. This results in the GUI starting to come up, and then crashing. Disabling Nouveau may differ some on Ubuntu, but on every desktop platform it might be a bit more involved because desktop installations tend to use the initrd “initial ramdisk”…even if you blacklist Nouveau from “/etc” (and the NVIDIA package itself will do this) it may be necessary to further blacklist Nouveau due to the initrd being an essentially independent initial operating system.
In order to fix it you have to be able to log in. One way is to have good timing and hit the ctrl-alt-F1 or similar hot key to get to the console (no GUI, thus no crash…then ALT-F7 to get back to GUI for testing). Ubuntu 14.04 seems to use older init scripts instead of systemd, so here is how to get text mode boot temporarily from the grub prompt in 14.04:
When you start up and grub briefly shows up highlight the entry for your Ubuntu boot, and hit the ‘e’ key. This gives you a primitive editor (it’s annoying that automatic key repeat doesn’t work…there’s a lot of tapping keys to move around). There will be a line which looks something like this:
linux /vmlinuz-3.13.0-135-generic root=/dev/mapper/vg_sda5-ubuntu quiet splash ro
…edits here are temporary until the next boot.
I tend to remove the “quiet” and “splash” part…I want to see boot text. I also append to the end (space separator):
…this might get graphics up if everything else is correct.
If your system still doesn’t boot correctly you may want to go to text mode by adding “text” to the end of that same line in grub. You’d hit the ‘e’ key, go to that line I mentioned, remove splash and quiet, then append “text” to the end. Probably you want to have the “rd.blacklist=nouveau” in the line as well.
Don’t use the enter key…you’d just be introducing a line break. Use ctrl-x to execute with that edited entry. The edits go away upon next boot. If you must go to text mode you may want to make copies of dmesg output and lsmod output. scp can be used to copy to another computer (or SD card, or whatever you want).
If all works well then you can probably make some edits and update grub and you’ll be set.