Holy crap. One low level format (zero write), fdisk, format, fresh OS install and four hundred patches and updates later, I now have a working computer again. Damn you Microsoft!
Actually it was only seventeen patches and updates. Seventeen! For Win98SE and MSIE 5.5SP2. And that actually was not all the patches and updates, there were more than 30 available for Win98SE and MSIE 5.5SP2, but my configuration didn't require them all.
You'd think a 'cumulative patch' would mean just that, but it apparently only applies to 'critical' security updates. Functionality (bug fixes) and low-risk security updates are not addressed by 'cumulative' patches. I used to like reformatting when there were only three or four updates.
So confusing. I would prefer that Microsoft issue cumulative 'Service Packs' like they do with W2K and XP. Nope, gotta go sifting through all the updates and bulletins and KB articles to find which ones you need or don't need. Grrrr....
This is the last time I'll do that. I'm going to Ghost an image of this install, burn it to CD-R, and keep it for any future format/installs.