Wireless Access

I have a Dell desktop that connects to the Internet through a wireless router and cable modem. Internet access is always up. I also have a Dell laptop with an internal wireless card. I want to connect the laptop to the Internet through the wireless router. When I open a browser on the laptop, it says no wireless network available.

The desktop is new. With my previous desktop (also Dell), the laptop connected to the Internet with no problem. Can anyone help?

Thanks,