Personal information and files on your wireless network can sometimes be seen by people who pick up your network signal. This can lead to identity theft and other malicious acts. A network security key or passphrase can help protect your wireless network from this type of unauthorized access.
The Set Up a Wireless Router or Access Point wizard will guide you through setting up a security key.
Open Set Up a Wireless Router or Access Point by clicking the Start button , clicking Control Panel, clicking Network and Internet, and then clicking Network and Sharing Center. In the left pane, click Set up a connection or network, and then click Set up a wireless router or access point.