Sorry, I can't help you as I don't have that problem with my Gateway
Laptop. I had 9.04, 9.10 and now 10.04 on it and when the power plug
is disconnected it sounds a chime and reports in the lower right
corner that the power has been disconnected. On reconnection it
reports that and carries on as usual. I think that is the way it is
supposed to work but some hardware is a bit fussier.

Have you tried an internet search to see if anyone else has that
problem with your make and model?

May be that Ubuntu figures the battery won't last long enough to back up
your system properly and hibernates. My system shuts down when the
battery is about 10% charged or 90% discharged with out so much as a
warning. How long is won't last long, this is likely the problem. When
you mouse over the battery symbol how much time is figured to be left in
the battery?

right now it does not give hours or percent, it says "Laptop battery is
charged."

Since the computer is at least 6 years old, I'm wondering if my new battery was
not doa for being in storage too long.

You say that the computer "...runs fine on battery alone..." and then "...won't
run long on battery alone."

So, which is it? And how long will it run on battery alone?

And what, exactly, do you mean by "cannot be revived"? What do you have to do
to get it running again?

Sorry, was not clear.

It is a Pentium 4 and will drain the battery in 1.5 hours or so, depending on
what's running on it.

When Ubuntu 10.04 is running, connecting or disconnecting the power supply will
cause it to sleep or hibernate, I'm not sure which.
Connecting or disconnecting power supply during startup, when 10.04 not yet
running, has no effect.

In whatever state it's in, the machine must be turned off and restarted to
revive it.

Hard to check with previous battery, which has truly failed. Changed battery and
upgraded about the same time.

Thanks for the clarifications.

Have you looked into a BIOS update?

You upgraded Ubuntu rather than a clean install of 10.04?

I have not considered a bios update.

I installed 10.04 from an image disc without first deleting 9. I think. I don't
recall doing anything to delete 9, not sure I know how.

If you didn't choose to do an upgrade then the previous version would
have been automatically deleted by the new install.

On my computers I have to have the cord unplugged to get discharge
info. If you can't do that I would guess that to be true. I think I
got the replacement battery from a place called computer batteries for
the other half's machine.

Actually, I have replace the battery twice this year. The first try was from an
online discount place, it was DOA.

Second try is from Toshiba, at twice the cost, and appears to run ok, other than
this problem.