How to uninstall ms office2003

Hi,

I am not able to remove or install ms office2003.
In my system first installed ms officexp then installed ms office 2003. now i am run the msoffice2003 setup.exe get error

"This patch package could not be opened. Verify that the patch package exists and that you can access it, or contact the application vendor to verify that this is a valid Windows Installer patch package."

pls help me