That seems to have been the thicket.  Thanks!

To recap for future reference:

When a new kernel is installed from an update, purge your nvidia drivers by doing this:

https://wiki.debian.org/NvidiaGraphicsD … stallation

Then make sure you have the Linux headers installed, I did that like this using the 6.12.90 kernel as example:

First search to see if they are installed:

sudo apt search linux-headers-6.12.90*

And to install, if not:

sudo apt install linux-headers-6.12.90+deb13.1-amd64 linux-headers-6.12.90+deb13.1-common

Re-install the nvidia drivers by following this:

https://wiki.debian.org/NvidiaGraphicsD … tification

I think I'm used to this all happening automatically on other distros.  I was using xubuntu.

Thanks all for your patience and help.
GrimLok