Problems with Nvidia driver in Ubuntu 16.04 LTS

New computer, with a Nvidia Quadro M4000 card, and came with Ubuntu 16.04 LTS loaded.

The default driver was Nouveau. I'm certain that I've correctly disabled it, because now ruing 'lshw -c video' shows me that there is no driver! In fact, I can't get past the login screen. When I login, it just crashes back to the login screen.

I was (finally) able to figure out how to stop lightdm from the tty console. I then ran the nvidia driver installer. It complained A LOT. A lot of the problems were due to security and keys.

I think the problem is related to "secure boot". For example, this thread: http://askubuntu.com/questions/76113...vers-dont-work

I can't reinstall the OS on this computer. I have to try to make it work, as is. Is it possible to tu off Secure Boot, so that Ubuntu can load the installed driver without asking for a key?