If you are connected directly to your modem, buy a router. They come standard with a hardware firewall which will give you additional protection to incoming attacks. Make sure your router is not using the default password as you set it up. Also, make sure wireless internet from your router is secured with a password. Don't leave it open because you don't care of other people use your internet. This gives other people direct access to your computer and also allows them to view your internet traffic.