Hacking means breaking into someone else's computer without permission. Although hacking is classified into several levels, from defacing the home page of a school website to breaking into the school network to change examination marks to breaking into government departments of national security, it is illegal regardless of the hacker's reasons and motives.

It's become commonplace to set up a home network in order to share Internet access with more than one computer. With the latest wireless-network technology, the network can expand beyond the hassle of laying a cable. These networks often have security vulnerabilities and hackers can easily attack and gain control of your computer. Installing firewall software can control the data traffic of your computer and prevent possible hackers' attacks.