Internet wifi with Laptop Dell Inspiron 6400

The Wireless adapter is all you need, provided you have a wireless router at home to connect to...Have you tried to use the built-in wireless adapter?

Should come with a builtin Intel Pro Wireless. If this is so, you just need a internet connection provider and a wirless router.

we have router
and otherlaptop is connected.
Something about this particular laptop.
Was told that it needed an internal card???
what is that?

It's a mini internal wireless card. Assuming the laptop is running Vista, when you click 'Start' and 'Connect to' if it's not shown then you don't have one. You should be able to plug in the USB adapter to connect wirelessly, but need to install the driver first.
Also check the internal is present but not switched on...
http://support.euro.dell.com/support/topics/global.aspx...