I believe the problem is solved. Windows was TRYING to install the same
update day after day with no result. I installed it manually and now I
don't get anything to update when I turn off.
For the past couple of weeks I've been getting updates to Windows when I
turn off. That seems excessive to me. Does is seem right to you? So many
updates?
Maybe you can try to do a manual Windows Update from Internet
Explorer, Tools menu (when you have some time) and let XP sort of
catch up if it is behind. You can watch it as it works and make sure
there are no problems that you are not seeing when it is shutting
down.
There could be a lot of updates and maybe your computer is never
running long enough to catch up, so it does the best it can in dribs
and drabs. Some updates are quick to download and install and some
take longer.
If the updates are downloaded in the background, they will want to
install when you shutdown and you can see the messages telling you
this is happening. I let mine download them in the background and I
install them manually on one computer and another just does everything
automatically and installs them at shutdown.
Once you get caught up I think the future downloads will be smaller
and faster with maybe with less frequency that you seem to be
reporting.