If you dont want Norton Identity Safe Vault to disable the browser password manager then Open Norton Product UI-> "Settings" ->"Web" -> "Identity Safe" and open "Browsing Options" UI and set "Turn off the browser's password manager" Tri-State option to "No".
You can enable your browser password manager in IE from "Tools"->"Internet Options" ->"Content" and click "Settings" link related to "AutoComplete" section and enable "User name and passwords on forms" and "Ask me before sacing passwords" check boxes.