If it has Windows 7, it does not. Microsoft has a lightweight free antivirus called Microsoft Security Essentials. It's automatically installed on Windows 8, but you have to download it from Microsoft's website on your own. I believe this computer had a trial for Norton on it, but I recommend the Security Essentials.
As with all Windows computers, it comes with a 30 day free trial of Norton Anti-Virus. After 30 days you may choose to purchase further protection from Norton or you can download one of the many free anti-virus programs like Avast or AVG. Personally, I don't like Norton and I purchased protection through Viper.