This is one of those things that would require a little hands-on time rather than giving you advice.
For us to go through it step by step would take a lot of your time and essentially be a class in basic networking, except in a bad order with lots of teachers shouting differnt things.
Go back to basics.
Do what you did to get it working the first time you ever used it. Possibly even uninstalling the drivers and any software that came with it.
When you insert the card, does it make a "Doo - Dooot" sound? (lol - yeah I know, glad we're not talking cars: vrrrm-vrrrm vs brrrrum brrrum
)
That sound indicates a usb or PCMCIA card being installed. If it doesn't (and the sound is turned up) then your pc is not detecting the hardware.
If it does, check the little icon in the taskbar near the clock that looks like a laptop card device. There may even be a little 'speech bubble' with a tip on what to do next.
Click on either to get some more info on what the device is and report back to us.
While the card is out, write down the card details and tell us what brand and model it is.