Wireless connection issue dhcp works but no internet or ping to router

I have a Netgear N600 ADSL modem router. All devices connected to the router are DHCP and wireless. Two Netbooks (Win XP), a Wii, a Logitech Revue (Andriod), a Dell 630 laptop (Win XP Pro), a Toshiba Satellite laptop (Vista), and a Dell GX640 (Vista).

The Toshiba will get an IP, Gateway, DNS, etc but then has no connectivity. Can not ping router or other devices. Setting a static IP, Gateway, DNS, does not fix the problem. Rebooting the laptop and/or router does not fix. Firewall on the router is off. Connective via cable works good.

Dell laptop has same problem but after leaving the Dell sit wireless connected for 30 min or so it will start to work. If the Dell is rebooted it can not get back on the network for another 30 min to an hour.

All other device work fine.

Have removed all devices from the network and tried problem devices alone. No change. Made sure router and NICs have latest firmware/drivers.

Anyone have any ideas? Thanks

I would try plugging directly into the router and the modem in front of the router. If the modem fixes the issue try a reset of the router. If plugging into the router directly fixes the issue then it might be something with how your router is transmitting. That could be fixed with some frequency tweaking on the router's GUI.