All Windows Popup menus gone

[Bill[_5_]]

Windows XP Home Edition SP2: I have a
client whose Windows popup routine(s) are
presumably curropted. The main toolbar of
every component of MS Office 2003 and
the Start -> "All Programs" folder displays
only show the popup shadow. That is, one
sees the right-side and bottom edges of the
popup frame sized for the toolbar item
detected, but otherwise the popup is empty.

I've never seen this before. Any ideas on how
to fix it?

Thanks,
Bill