Her computer's up & running again - still have to R & R a couple of drives, but it boots to Windows, the printer works, music plays & her pictures display. Might even look at replacing the secondary case fan, it's always been a bit noisy anyway.
Took the dying drive out of the case, rotated it 90* (set on the floor on edge instead of bottom down), directed a fan at it and used an old, old version of Ghost to copy it over to another drive. The drive actually performed better than I'd expected/hoped for, it ran long enough to go through 3 attempts at Ghosting, one Scandisk w/o a surface test and another Scandisk w/surface test, and another Ghosting. The Scandisk's were run 'cause Ghost stopped at ~98% saying it couldn't read some sectors, still couldn't read sectors after 1st Scandisk, and still couldn't read the last <200MB on the last Ghosting. That's when I said screw it, plugged the "new" drive in as primary and hallelujah!
Not sure yet what's missing, but it doesn't seem to be essential Windows files. We may never know what's not there, but right now I'm just happy the damn thing's running again.
I did find that some of my >12yr old 3 1/2" floppies still work. Dug out the stash I kept for basic work such as this and most of them can still be read.
I've been checking hard drive prices on Amazon, going to get another 60GB drive to hold a Ghost image of this drive before she uses it.
Thanks for the help!
ETA: Never did hear back from OnTrack.