I just thought I would like to thank everyone who sent helpful advice
hoping to cure my old Dell Dimension from freezing up.

Well I have been off line to this list for a week or so, and have
carried out my normal maintenance check.

I checked the MB both electronically and visually with a magnifying
glass. No damage found.

I cleaned the case internally and the fans, both power pack and processor.

I checked every connection, cleaned and reseated them.

I put in new RAM after blowing the slots. 2 x 512mb this time as per Dell.

In general I found nothing to cause this problem that affects 10.04 and
not XP so

it may be that it is the D: HD but i cannot find anything wrong with
that either.

I will use it anyway and see what happens.

In the meantime this is just by way of an update.