User credential

I configure users to be Administrators on their workstation and I connect
them to domain. when I do the windowsupdate all is well (I'm the
asministrator of the domain) but when my users loged in they failed (you do
not have permission to update Window). Looking at the user profile I find
that they changed to be debugger user. All was fine until few months ago on
Windows 200 pro and Windows XP pro. Any idea what changed their rights? Even
when I change the user agai to be in Adinistrators group they get only part
of the updates. In XP it's worth, the user is not able to update and can not
create a resore point.

Thanks

Dolly