Vista - Setting Up Norton secure with xbox360

Even if you have different firewall; most of them should have been
similarity to norton.

Go to norton security option; go under General-Settings ->Trust
Control. Add your xbox ip there. Most of the time if you have dynamic
ip; the ip will oftenly change everytime you restart your console/pc.
I suggest you set your router to allow only 10 pc user from range
100-110. So for instant:
My router ip
192.168.1.1

I would add
192.168.1.100
192.168.1.101
192.168.1.102
etc...110

When done; click apply and test it out. If your xbox sees the pc;
you're good to go. Click okay to complete your norton setting.