I recently sold my old MacBook to my brother. He has 2 PCs and 2 iPhones, both of which connect perfectly to the internet throught his modem/router (a BT Business Hub). The Mac, on the other hand, just won't connect to the internet. Airport connects to the router, but cannot load any web pages. Connecting by ethernet does not appear to help. This Mac will happily connect to any other router except this one. Is there some arcane setting somewhere that might fix this? Thanks.