Appreciate everyone's input. I've made notes of it for any future reference. Never got to use any of the suggestions BECAUSE...

Before the suggestions had arrived things got to the point where I simply, unutterably, COULD NOT get beyond the Bios window. I had wanted to correct it short of what I did do; namely use my back-up (cloned) HDD. That did the trick. So I'm back up and running; it's started twice now - no problems - I lost a couple of emails and regrettably a lot of my financial records which, though on back-up floppies, did not end up replacing the missing information. I was able to do that line by line with credit card records and my checkbook and bank account records. I won't say how long it took!!! Can only guess why the floppies failed to replace the records--it's a bafflement as the King of Siam said.

efc: Haven't authenticated XP with this change. Because it had already been authenticated before I did the clone.

rik: Yeah re the hard drives. It was the Samsung drive that was the master before this whole problem started. The Seagate was the slave. Right now, those designations are, of course, reversed.