1)Open the web browser that you use: Firefox,Google Chrome,IE,or Opera and type in the IP address for your router,and press the Enter key.
2)A window will open and then type in your routers default username and password,and press the Enter key again
3)Navigate to the Wireless Security\Network Security Settings Tab and open it to locate or change your WEP or WPA Security Passphrase.
Use WPA because it provides better security.
4)Write this Security Passphrase down and put it in a safe place to access when needed.
5)Save settings and close your browser.