second monitor suddenly not detected (resend)

[Colin Law]

On Sat, 26 Sep 2020 at 09:58, Karl Auer <kauer at biplane.com.au> wrote:
> ...
> It really feels as if Ubuntu has somehow "forgotten" it's video
> settings. Is there not some way to re-install the graphics system?

It could be hardware of course.  Try booting from a live image, or/and
boot into windows if the machine has a windows partition.

Colin