parallel ports don't support hot plugging? til!
I knew serial does, win9x actually instructs you to plug in a serial mouse if it doesn't detect a serial or PS/2 mouse is plugged in... it shouldn't prompt if you plugged in a USB mouse either but that sometimes doesn't work.
@noiob that's why it only prompts you to plug in a serial mouse, at best Windows will never see a PS/2 mouse you just plugged in. I know, I lived through this shit.