I ran across this on a Netgear router. In the end we found that an older firmware was working fine. Their latest had bugs. Your post is light on details. If this router never worked, then return it for another model.
I have a Belkin F5D8636-4 v2 N Wireless Modem Router. For some reason, it will only connect to the internet if the wired computer is plugged in and on. I tried starting the router without it plugged in and it kept trying and failing to connect to the internet. As soon as I plugged in the wired computer it connected to the internet.