Ed,

I forgot this. Anything here helpful?

https://wiki.debian.org/NvidiaGraphicsDrivers#Version_375.66_.28via_jessie-backports.29

Here are some old instructions for installing the nvidia binaries, in case
you need to go this way. Adjust versions and possibly replace "sh
NVIDIA..." with "bash NVIDIA..."
http://forums.debian.net/viewtopic.php?f=17&t=58994&p=341825#p341825

You may or may not need to add "nomodeset" to your boot command. I've had
it go both ways, depending on which nvidia card I was using. Black screen
is the hint for this.

fsr