D-Link DIR-615 Wireless Not Connecting To Internet

I am trying to get neighbour wireless router working. He has a D-Link DIR-615 Wireless N 300 Router. I have gotten the router working by manually putting in his PPPoE settings. Now with a wired XP SP3 computer connected via Ethernet, it can access the internet. We then configured his router for WPA2 with AES encryption. We were able to connect up his phone which can handle a WiFi connection. He was able to surf the web using the WPA2 passphrase. So far, so good. The last bit was the upstairs computer which has a PCI D-Link wireless N card in it. That computer runs XP SP2 and we have not been able to get it to connect to the internet.We have tried both Windows networking, and the D-Link Wireless management software. We were unable to get WPA2 working, so we tried WPA, WEP, and finally no security. In each case, we can get the computer to connect to the router by putting in the passphrase (except when no security), and the status changes to Connected. But then browsers are not able to open any internet site.

I have checked the ipconfig settings, they seem to be correct. DHCP is providing the computer with a valid local IP (192.168.0.102), and the gateway is correctly listing the D-Link router.Subnet mask is 255.255.255.0. The downstairs Ethernet connected computer has an IP of 192.168.0.100, so they are on the same subnet.We have tried turning "Windows Wireless Zero Configuration" service off, and also tried with it on.We have switched between using the D-Link client and allowing Windows to manage wireless settings. It finds the wireless network, and connects with the passphrase with a good strong signal, but internet persists in not working.I do not have MAC Filtering turned on.I have turned off the Windows Firewall on the wireless computer. What else am I missing?