If he doesn't get a 192.168.x.x IP then either the encryption passphrase is incorrect... eg zero instaed of "O" or his wireless card cannot use the encryption that the router is set to... eg WPA2 or the router is MAC locked or similar.
But either of these circumstances would prevent the wireless from connecting which it has done.
I would use the wizard in network and sharing to diagnose the problem - probably that Windows or a Anti Virus / Firewall is blocking it. Setting of the network type in network and sharing is crucial - should be a "home" network.
Ex <n>ildram , been to SKY MAX - 15,225 Download
BE Unlimited - 21,000 Download 1,200 Upload ON THE LINE THAT SKY COULD ONLY PROVIDE 15,255 DOWN AND 800 UP ON!!!,
Moved house, now BE Unlimited 6,500 Down, 1Mb/s up - gutted!
FTTC Cab installation commenced 12th April - expect full 80 / 20 - bye bye BE, hello BT Infinity, install date Friday 10th August!