windows update downloads updates but then dies

My friend has WinXP Home and is having problems doing his Windows updates.
The program that is running the update process seems to be not working
properly: it scans for needed updates just fine, finding, say, 9 critical
updates needed. However, if I try to remove any of these updates that it
automatically puts in its to-download-and-install list, the 'Remove' buttons
(next to each update in the list), though enabled, do nothing when clicked
on. This is the first symptom.

The second symptom is that upon trying to download and install, it proceeds
to download all the updates just fine, but as soon as the downloading
process is finished, instead of then proceeding with the actual installing
process, it just sits there and does absolutely nothing.

Because the 'Remove' buttons don't work as well, I'm thinking if we could
just uninstall the program that does the whole update process, so that it
would be reinstalled on the next attempt to do a windows update, that could
likely fix things, but I'm guessing here. Does anyone know how to uninstall
the windows update program itself (I assume it's a java program downloaded
from the website if it's seen that the computer doesn't yet have it)?

Or if anyone has other ideas what would make the 'Remove' buttons not work
and the process just die after the downloading is complete, please advise.

thanks,
-dg