certain Microsoft updates do not install

I'm using Microsoft office 2007 sp1 enterprise on a high-end Dell laptop...
two downloads refuse to install. They are the latest Silverlight download
and security update for Microsoft Office 2007.
Constantly the yellow shield remains in my icon tray. I've tried using the
custom option and unchecking him but they will not go away.

For the Silverlight update, I've tried all the obvious things, such as
reinstalling Silverlight or trying to uninstall it from the original
installation program.

For the Microsoft office I've tried all the obvious things such as running
office diagnostics. I've gone to the office update website and it cannot
determine what updates I need because it fails and it gives an extremely long
and varied explanation of why(it would take hours to try all the different
possible solutions).

It's very frustrating since all I want to do is use Microsoft software not
be constantly debugging it.

Does anybody have any ideas?

Thanks
Bob