I had a real problem trying to update xp w/sp2 from windows update . trying
to install the new 3.1 windows installer over the 3.0 one in sp2 kept giving
me an access denied error. finaly fixed it by following the procedure in
http://support.microsoft.com/kb/315353 it appears that even the OS needs
permission granted in the regestry when updating itself with new files. Great
idea for anti trojans but a pain for the normal guy. hope this helps someone