Try the router defaults, then broadcast the SSID and use the WPA/WPA2 PSK security.
This is noted in the CNET Networking Forum but I've summarized it to one sentence for brevity.
every day i have to reset my router, so my netbook can connect. the router is an older dlink wbr-1310 and my netbook is an emachines em250 with windows 7 starter edition. i've updated the software for the router and still no luck. my son's xbox 360 is connected wirelessly to this router with no problems and after i reset the router my netbook connects fine all day long, but the next morning i have to reset the router again to connect my netbook. i also have two desktops connected to the router, but are wired not wireless. thanks in advance, sorry so long, but was trying to get everything in. davemonkee