On 7 July 2018 at 23:09, Ken Heard via talk <talk@gtalug.org> wrote:
The computer has Debian Jessie installed in it.  One day recently after starting it, the BIOS identified the hardware.  It went as far as to display the line "Verifying DMI Pool Data ..................." and then stopped. The rest of the monitor was filled up with series of 99s

I then tried to use a the Rescue mode on a Stretch net install disk. The opening menu of the disk appeared on the monitor, but it did not respond to input from the keyboard.  I consequently could not select the rescue option.

I checked the keyboard on another computer where it worked.  Using the keyboard from the other computer on the one not working also did not work there.

The net install disk can be opened on the other computer.  In fact I used it there to install Stretch on it.

I did a Google search, but all the references I found assumed ability to open the computer from a rescue disk.

Does anybody know why this problem would arise, and what to do about it -- if anything -- by way of fixing it.

Regards, Ken Heard

This link: https://www.computerhope.com/issues/ch000474.htm suggests the problem is lower level than I thought (BIOS rather than OS, which may negate what I've written below).  You could take a look and see if their suggestions help.  Doesn't look like a fun problem to tackle, sorry.  As they suggest, start reseating or better, disconnecting internal components one at a time in the hope the problem goes away on one of them.

I use Knoppix ( http://www.knopper.net/knoppix-mirrors/index-en.html ) almost exclusively for rescue - I would give it a try.  I'm inclined to suspect a hardware problem, and if you get the same error after burning Knoppix to a USB stick and booting, that would be ... well, a partial confirmation.  Only partial because Knoppix is still, at its core (I think ...), Debian.

If it does boot, you have a much friendlier and better equipped interface for system exploration and recovery than the pure Debian rescue package.

--
Giles
https://www.gilesorr.com/
gilesorr@gmail.com