I list below the steps how to completely uninstall NAV before you install a new AV product.

The following works with NAV 2002 and NAV 2003 but Im unsure about 2004. You must complete these steps in the right order and reboot the machine at various stages when asked.

Uninstall Norton Antivirus
- It will ask you to Reboot

Uninstall LiveReg
Uninstall LiveUpdate

Delete C:\Program Files\Symantec\Norton Antivirus
Delete C:\Program Files\Common Files\Symantec Shared
Delete C:\Documents and Settings\All Users\Application Data\Symantec\LiveUpdate
Delete C:\Documents and Settings\All Users\Application Data\Symantec\LiveSubscribe
Delete C:\Documents and Settings\<username>\Application Data\Symantec

On Windows 9x/ME,

replace C:\Documents and Settings\All Users\ with C:\WINDOWS\All Users\
and C:\Documents and Settings\<username>\ with C:\WINDOWS\Profiles\<username>\

.