Mine didn't come with one so you'll have to tell more.
Also, the most common threat is still us. Too many fall for social engineered exploits such as a web page that announces "Your Flash Player is out of date. Click here."
Too many do that.
No antivirus or firewall stops that as this is a Personal Computer and if you want to install a trojan, you may.
I am not sure if the security suite for windows 7 is good enough. I would like to know if I should download a better anti-virus and firewall?