Systemworks problems with W2000

I am having problems with Norton Systemworks running in W2000. After installation it works ok for a while and then the Liveupdate stops working. It asks me to reinstall it. When I uninstall from the control panel, all seems ok. When I try to reinstall Systemworks, it tells me I have a previous copy of Norton Antivirus which must be uninstalled first. How can I remove all reference to Norton products in the registry so that I can do a clean install ?