I am having the same issue with a friend's second laptop. Thinking the older one was "toast" he bought a new one. I worked on the one that he thought was gone and got it working fine, at MY house. When I took it back to HIS house, where his new laptop connects to the internet just fine, I could not get any connectivity at all. It "sees" the network but will not connect to the internet. I found a possible solution on line and you can check it out to see if this may be the problem. It relates to two laptops having the same IP address and how that does not work. This link will get you to info as to how to change the IP address on one of the laptops. I have not had a chance to try this on my friend's laptop but I will when I visit again.
http://compnetworking.about.com/od/i...t-problems.htm