Can't un/re-install office XP

[JCoogan]

Much like Sikander, whenever I try to open an office
program windows starts trying to install OfficeXP then I
get the message, "This patch package could not be
opened. Verify that this patch package exists, and that
you can access it, or contact the application vendor to
verify this is a valid Windows Installer patch package"

I have tried uninstalling OfficeXP, but get the same
message.

I went to the Microsoft support site which said for
machines running earlier than XP try running an installer
clean-up file MSIC.DLL, but it gave no clean-up file for
XP.

I am at an impasse, I can't use any of the OfficeXP
programs and I can't uninstall or re-install it. Any
ideas?