W U not admin

I have a small domain with about 15 users. All log in as users and do
not have administrator priviliges. Every machine is Win2k SP4. I have
each machine set to download updates and install them every day. It
appears to me that the updates are being downloaded but not installed
until I log in to the machine with an administrator account. Is this
the way it is supposed to work? From my understanding of the documents
I have read it should install the updates in the background without an
admin having to log on. Do I need to change some additional settings
to accomplish this? If so could someone please provide those. Thank
you for the help.