2GB microSD not responding

I haven’t had this problem, but I don’t have a Kingston card, so that doesn’t count.  I’m curious, though.  What if you use the Sansa Firmware Updater to change the region and load the PacRim/Asia firmware?  You get the region drop-down if you click on the updater icon and select “Check for Updates Now”.  There may be no way to roll back, but you can try overwriting regions and see if that works for now.  Maybe the American firmware just didn’t load right…