"Paul D.Smith" wrote in message
.. .
...snip...
Some PCs have non-rechargeable system button cells that can simply be
replaced.

Sounds like you have a bad NiCAD/NiH battery and bad connections. On my
Compaq (aren't Compaq and HP the same these days?) the socket is notorious
for coming completely loose from the motherboard resulting in the whole
thing failing. My PC was dismantled carefully, the socket soldered back
with some suitable copper wire where the MB contacts had failed and then
the whole socket epoxied to the motherboard for further strenthening.
Should it fail again, I'll never be able to repair it again but frankly
I've repaired it once too many times for my liking already.
I am in exactly the same position: We have established that the connector
between the mobo and power socket does come loose on these HP laptops and
then presumably the power in stops providing power to the rail comprising
the CMOS battery charge circuit. There might well be nothing wrong with the
(reasonably newish) CMOS battery. Since this time I have spoken to a
friend in New York who reports that he had exactly the same problem with TWO
of these computers bought for his kids! I dont think there can be much
doubt any more about what is causing this, despite some responder's mention
of the need to check voltage measurements before soldering back what
everyone seems to agree is the broken connection.

Where did you find someone to do the repair? Or if you did it, was the
soldering a difficult one comprising lots of tiny connections?

Paul DS.