how to remove the password on minisd (kingstone 1gb)?

i have the same problem too.well i just bought nokia 6280 as well.my memory card is kingstone minisd 1gb.for the first time i can open the card folder in my phone and put some files in it,and then after a week then when i want to open the card in my phone it ask me to enter a password.i really sure that i had never put any password on the card,so now i cannot use the card any more because of the unknown password and i cannot format the card in the computer aswell.so can somebody tell me what had happened and how to solve it.now i really miss the old time when the card was still ok.can anyone pleeeease help to solve this thing!i'm begging