Can a site prove it is you using a banned mac address when using a pcicia wireless network card.?

The first thing is you are referring to a PCMCIA card. The second thing is most sites never actually log your MAC address because they, often times, don't even see it. If your ip address is banned, there are a couple of ways that you can go about getting on. The first is to call your provider and ask them to give you a new IP address. The second is to release your ip address from your router and get a new one. You can keep doing this until it changes as most internet providers give dynamic ip addresses. The third is to get an ip spoofer. This will allow you to go to sites and what they see is the ip address that the spoofer provides.