Setup: Motorola Cable Modem --> Airport Extreme; Airport Express as range extender; Sharing a public IP address; IP range for devices is in the 10.10.x.x range. I have 12-15 total devices connected. Almost all are Mac products, but there is also a few random multimedia devices. Every device on the network works flawlessly EXCEPT my new MacBook Pro. It gets a proper IP address from the network but simply pulls down nothing from the network. When I open Safari it shows the request going out, and then the browser waiting for something to come back. No application can get data down from the network. I've reset, restarted, etc... I started configuration from scratch on the Airport. No dice. I did switch it to Bridge mode and got the Double NAT warning and it worked ok that way for awhile, but now doesn't work that way either.
You sure the wireless in the new laptop is good does it work perfectly elswhere? I mean why tottaly reconfigure the airport extream if everything else is working correctly..? Have you tried connecting to just the extender and the aireport extreams wireless? Does the cablemodem have its own wireless you could try? And last one but have you tried hardwire to make sure everything works as it should? Oh can you ping one of your media devices? Sounds like a DNS issue to me. See if you can ping yahoo.com if nothing try to ping yahoo by it's ip if that works then DNS issue..