Sony Vaio says it's connected but won't bring up internet.

I am having trouble with my Sony Vaio. We purchased it about a year ago and then in the fall purchased another, My husband took the first (black) laptop to the desert with him and was able to connect to the wireless connection no problem. Ever since he has came back and we purchased a D-Link routerit won't connect. We have tried the wireless wizzard and it doesn't have the model router we have on the list. It now says that it is connected to the network and has local and internet accss and has a very good signal but when I bring up the internet it gives me the "cannot display page" :confused I do the diagnose problem thing and it says that it cannot find yahoo.com through the DNS. I have Internet Explorer 8 and Mozilla Firefoxloaded and neither work. Also when I connect the ethernet cord to it it connects just fine. Please help! I have found many site ad tried many things and it is all so frustrating! :crybaby I am not all that computer savvy so lamens terms and detailed instructions please!