Hi,
Do you have HP recovery disks or not?
Your last post:
"FWIW, this particular set of diagnostics thinks the HD is just fine, but if I let the software "Restore to factory defaults", it craps out pretty soon:"
Prevoius posts indicates no recovery disks.
You said:
"I wiped the HD, not realizing that HP shipped it with a system restore partition AND WITHOUT recovery disks".
I am not clear on what is happening.
If you have retail Win Vista or Win 7 install media you should not have problems installing same.
You either have faulty hardware or no valid insatllation media.
Jaco