I don't know what step you're at, so I'l just throw out a bunch of ideas and maybe one will help you.

1. Run 'kudzu' to see if it will find and configure your network card for you
2. Make sure the kernel-pcmcia package is installed. I'm most familiar with redhat, so I'm not sure if the name is exactly the same in mandrake. Run 'rpm -qa | grep -i pcmcia' to find out.
3. Try 'service pcmcia stop', then pop the card out. Wait a second, then run 'service pcmcia start'. Then pop that card back in.
4. If none of the above work, run 'lsmod' and post the output here so we can hopefully help you further.