HP VISTA And NIS 2008

I have Compaq Presaro F730US. O/S is Vista Home premium

Under HP Total Care Advisor, under the item called "security", it
shows
that the firewall is off.

Instead of renewing Norton Internet Security 2007, I purchased Norton
Internet security 2008.

Now secutiy shows that this item has to be fixed.

If I turned on Windows firewall, wouldn't I have 2 firewalls?

Why should I turn on Windows firewall, when this setting worked in
NIS2007?

thanks