The balky hard drives failed to boot terminally. Not only did the main drive fail to read, but so did both backups. The drives all continue to be readable as external devices; they simply won't book. FIXBOOT doesn't work. FIXMBR doesn't work. Running a Windows Repair installation doesn't work. None of the drives have anything physically wrong with them; they've all passed diagnostics. Even the computer itself has had its motherboard replaced. So maybe starting over with a fresh Windows XP installation will finally produce a stable system on that laptop. I'm not especially hopeful, because I've had nothing but grief from this computer, to the point of starting to hunt for the equivalent Latitude (the D600, which I can find for under $300 on eBay) and simply giving up completely on the Inspiron. But nonetheless, it can't hurt that much to try, so this evening I started a "bare metal" install of WinXP, including the laborious process of re-installing every Dell driver and downloading the latest updates. Right now I've re-installed Office and am waiting for all of its updates to install. Getting all of its software re-installed will probably take days. And then it may simply stop booting again. I have no idea.