Take a peek into the PC card slot with a flashlight. Use the handle of a plastic spoon to hold the doors open while you shine a flashlight in there. Check every pin to make sure they are not bent into each other.

I had that problem on my Wallstreet - one of the ground pins was bent sideways and shorted the pin next to it. I tried straightening it out, but it snapped right off! Luckily there are other ground pins, and my cards seem to work just fine without this one.