All the sudden when I pulled out my flash memory pouch filled with flash drives and SD cards, 3 out of my 4 SD cards will not be recognized by any computer! It's like they all died....2 were the exact same 2GB and one was a 1GB.
Are they name brand microsd cards? Non -name brand ones tend to die fast. Though it is a bit odd for 3 of them to die. Are the contacts dirty?
Also if you are on an xp machine you should use the "safely remove hardware" option to avoid any problems. Borked a number of flash drives like this. Don't know if its needed on windows 7/vista, its just habit to do it now..