Why can my Dell Laptop connect to wifi but not get internet through it?

So I am having the same issues as this: http://en.community.dell.com/support-forums/network-internet-wireless/f/3324/t/19406038.aspx 

whole post. I have done everything that this forum and two others with the same information, and still no avail. My computer reconizes that there is internet other computers can connect to it. I just am unable to get on and serf. I have tried the wireless network connections and changing the protocol version 4 and 6 to Obtain an IP and DNS and still no luck! Reset the modem tried using a ether and hooking up to a different network. 

I have gotten the two errors of DNS server not responding and connection between access point, router or cable is not working.

PLEASE HELP ME!