Need help connecting Macbook

I just bought my daughter a 13 inch Black Macbook. We took it out of the box and attempted to hook up wireless to the Belkin N1 router in her apartment. The blue line in the address bar would only go to the first "W" and stall. We have a Windows laptop also and that works fine through the belkin. It connects like a champ. I took her Macbook home and it connected with my d-link 655 net perfectly.
I took it back to her apartment and was not able to connect to the internet with the Belkin. It show the network as connected but no internet. I even plugged the cable directly to the port and nothing. I took it to the Apple store on 14th Street in NYC and it worked fine. Back at her apt nothing. It connects to the network but not internet. I was able to piggy back a net and it worked good.

Please help

ISP is RCN