Try some googling for you card and see if there have been linux or binary drivers released. Some cards are just wacky.
I have a few D-link cards, and D-link is a big manufacturer. Well, for the cards I have.. the chip manufacturer won't release the specs for someone to write real drivers. There's a sourceforge project that wrote drivers, but they're not included in any distro I've seen (yet).
Search for the card, and look for the module that corresponds to your card. You can do a lsmod to see if it is installed and inserted when your box is booted, otherwise if available you can download and make / install the drivers.
If the module is installed and inserted into the kernel there are a few things you can do..
1. Ping.. open a terminal and type ping (router's IP if you have one, or a web address). A returned ping from your router shows you have a connection to your router, but maybe it's not routing the packets out to the internet. If you can ping your router, and ping a webpage (try www.yahoo.com
) then you should be good to go. If it isn't routing out of your router properly to the internet you can type "route add default gw (router's IP address) wlan0".
2. iwconfig... once the card is in, and the modules made and installed then you should be able to bring up your settings by typing iwconfig or iwconfig wlan0.
There's a bit of the info you might need.
Step 1 is to find out what module runs the card and see if you have it running or not.