Have you got a firewall running, may need to put your router's home page in the trusted zone, should be something like 192.168.1.something, the page you use to set up the router. This should happen on its own but had a similar problem on the wife's comp. running Zone Alarm.
May already be in there but would not hurt to have a look.
I thought most people turned off "Wireless Zero Configuration" or am I mistaken.