We don't have a product key handy for the Windows 98 disk, so I shut off the computer at that point in the Windows 98 installation. I assumed that I could boot from the Windows 2000 disk and blow away the incomplete Windows 98 installation.
It turns out that the Windows 2000 disk I have does not seem to be a boot disk. So much for plan A.
I managed to boot up with the Norton SystemWorks rescue disk and exit to DOS. But that DOS was unable to read the Windows 2000 CD. So much for plan B.
I managed to dig out the rescue disks that came with our desktop system. Booting up with that said "This is only for use with a Gateway system." So much for plan C.
(I have so far rejected plans involving floppies, because I don't have a floppy drive for this laptop. Perhaps I should try to borrow one.)
I will report on plan D when I figure out what it is.