>one-button mouse in X sucks, to say the very least. Having no USB, (and
>having no USB mouse either), is it possible to use a PC serial mouse

I can't answer your question, but I can suggest an alternative:
  buy a USB PCI card and a USB mouse for about $20 each. The docs
  say this is fully supported.

Related question though: I have a PowerBase clone which comes with
  OS/2 ports. Are they supported?