How to change a network password?

Hey, I'm a newbie mac user and I'm trying to use my parents wireless network. It shows that I'm connectd but I can't access the internet so I'm assuming I've entered the wrong password but, for the life of me, I can't figure out where I can change it. Any help?

I should also note that I have no problem connecting to other wireless networks.

System Preferences ---> Network ---> Highlight the SSID of your network ---> Click Edit ---> Change Password ---> Click OK ---> Click Apply Now.

Thanks

Thank you very much about this!!!!!!