W00T

My friend Marc held the answer.

It was, predictably, simple. Just reboot the machine while the drive is plugged-in.

Duh.

Worked, too.

Interestingly-enough, while the instructions said to change the jumpers to "master" setting, I opted for "slave" and they worked fine.

I found a treasure-trove of old, old data there. Old game files. Old emails. Old, old stuff.

I even found a pic someone emailed me from New York on 9/11/01. It was creepy, to say the least.