Won't connect to single wireless connection

Well, my friend got a MacBook for Christmas and this thing is money. However recently he's had difficulty connecting to his house's wireless network. He has no problem connecting to the wireless at my house (next door) or our friends house down the street... I tried a couple of things but no dice. I'm looking to blame their router, but the other guys that live with him don't seem to have a problem connecting to the wireless (the other computers being an iMac IC2D, iBook G4 and PowerBook G4). Any ideas? It just doesn't make sense to me, thanks guys!

He might be getting a self-assigned IP address on his network. The best thing to do if that is the case is to power-cycle the setup and he should then pull a fresh IP.

Do you mean reset the router? I'll try it, gotta make sure his roomies are okay with it, haha.