I'm running Debian V4.0R0 on an old Presario 7588. Yep, 128k RAM, 20th
century BIOS (I've been waiting to say that). IT runs well, no issues with
install or performance so far, but light usage.

The only issue I've had is that the screen resolution is limited to 640x480.
I'm not given any other options when I go to preferences.

Is there something obvious that I'm missing?

There is a BIOS upgrade available from Compaq (circa 2001) that says that
includes a video BIOS upgrade. I have not applied it yet. And have no idea
if it would matter. I'm not sure if I actually have to be running MS OS to
do the upgrade. I'm thinking I do not as long as I can build the upgrade
floppy on another machine. Problem is that the Presario is the only machine
I have that still has a floppy on it. But I can solve that one.

Any thoughts on what I should do next.