Uninstalling Norton 2003 Professional an

I follow all the directions, and the system says that I have successfully uninstalled Norton 2003.
When I the try to reinstall it, it says that certain parts of the norton 2003 are already installed and will not write over them. When you fine these files still in the computer, they are listed as,
UN_Norton_Antivirus
UN_Norton_Ghost
UN_Norton_Clean sweep
UN_Norton_anitvirus system 2003

These files are still in the computer, even though it has said that I had successfully uninstalled Norton 2003.
Even if you delete the files listed above, and try to install Norton 2003 again, It stll shows them to be present and will not allow maximum installation. You van not access these files period. What can be done?

Thanks