Enter the following address in your Internet Explorer or Firefox address bar, http://192.168.1.254.

Once the address is inserted, press the enter key and it will ask you for a username and password. The username is "admin" (without the quotations) and the password is also admin. The username and password are both case sensitive and should be lowercase.

After logging into the modem, you will choose Home Network at the top of the page, then go to Wireless, and then to Security.

There are three security options to use. Those relevant to securing your network will be WPA Personal, WPA2 Personal, and WEP.

If you will be using the WPA option to secure your wireless, disabling the serial number encryption will allow you to enter a custom password in the Pre-Shared key field. You can also let the router decide the password for you by leaving the serial number encryption field to 'enabled'. To view the serial number encryption password, click the 'click here to display' link to the right of the text box.

*If you want to use the WEP method to secure your network, choose enable under WEP, type in a random passphrase, then click generate. Key 1 will be your new encryption key.

Click the Save / Apply button to save your new settings. Upon completing the above steps, you will need to reconnect to your network using your new wireless key.

*Vista users may have to uninstall and reinstall their wireless adapters in order to reconnect to the wireless network.

For more information on security types you can follow the link here http://www.ehow.com/list_6330675_wireless-network-security-types.html.