Can you ping the internet by ip address? Try this
Code:
ping 75.126.162.205
ping linuxquestions.org
If it works for the numbers but not for the words you have a problem with domain name resolution. Check the contents of /etc/resolv.conf. It sounds like you are using a dhcp daemon to get your network connection settings from the wifi access point. If it's not setting the dns correctly you need to look into the documentation for your distro to find how to configure your dhcp daemon (I can't help you with that, I dont use dhcp)