Can't give any great technical advice but had similar problens earlier this year. Uninstalled Norton AV and Firewall and am unable to reinstall from CD, either the 2003 version or the 2002 version. I believe the uninstall procedure doesn't do a complete uninstall but leaves odd bits floating around in your system which prevent a reinstall. I now use AVG.
Will be interested to see what other replies you get.