Setting static IPs would affect connections elsewhere but for testing purposes it would at least rule out the router's DHCP assignment.
To change the laptops from DHCP to static you need to (assuming XP):
- Go into Control Panel, Network Connections and right-click the icon for the wireless connection.
- When the properties box opens, select TCP/IP and click Properties.
- Change the first radio button from "Assign an address" to "Specify an Address" and enter the IP that the laptop has been getting from the router.
- Enter a subnet mask of 255.255.255.0 (assuming the IP address is 192.168.something) and enter the router's address as the gateway.
- Change DNS from automatic to specify and enter the router's address as the first or primary DNS server. Click OK until it's all saved and applied.
You should then be able to type the router's IP address in a web browser and see the router's home page. If so, then try some web addresses.