Latest update kills my laptop video

[MR ZenWiz]

I just finished a "partial upgrade" of Xubuntu 20.04 that did not
originally complete on my HP-8740w laptop.  On reboot, the laptop
direct screeen video went from 1920x1200 down to 640x480,  the HDMI
monitor is not being recognized at all, and the Display settings calls
this the default and won't let me change it.

I vaguely recall this happening once before and I believe I downgraded
the nvidia driver to 390, but that was removed by the "upgrade."

How do I find/tell what the right nvidia driver version is and how to
install it?  I think it was using the noubeau driver, but I'm not
sure. It's late evening here and I can't address this until tomorrow
afternoon, hours after I need it up and running properly again. I can
substitute another laptop temporarily, but...

Thanks for any and all help.

Mark