Got it back. I thought the BIOS looked okay, but was wrong. The IDE controller had gotten disabled. Don't know how that happened--I certainly didn't do it. Nor did I explicitely reload defaults!
After system hung, I had to power off and on to reboot. Windows would not load--kept hanging, so I booted into safe mode (HD still working). Safe mode loaded fine, so I reboot. This got me into Windows, but my display resolution was wrong, so I changed both the resolution and the color depth. I then rebooted (as the system told me to), and from then on, NO HD. Something in that process evidently changed the BIOS setting.
Anyway, it's back working--the only thing I lost besides time is my HD activity light as I broke off one of the wires during one of the several plugging/unplugging of the HD cable. That CAN be fixed!