So the other pc is using the hub on the back rather than the wireless. I have used one of these before, is your "working" pc got an ip address of 192.168.1.X and a gateway of 192.168.1.1 ? (start > run > cmd > ipconfig)
it maybe your dhcp settings on the router, or your ip settings on your wireless card, compare what the settings are from the working pc and set them manually on the wireless tcpip properties, make sure the ip address is on the same range e.g 192.168.0.5 but the gateway needs to be the same... if this works then we can try and look at your routers dhcp settings
If you try to fail, and succeed, which have you done?