2gb micro sd memory card password

Hello,
i need a help plz help me....my micro sd 2gb memory card asking for a pasward.when im copying some file from my pc to my memory card its suddenly stop working.i dont know what happened.and then after some time I insert my memory card on my phone c1-01 its asking for a pasward.but I dint had locked it.i dont know what to do.plz help me.if my memory card data will be delete its ok.but I want my memory card work back again.....plz help me.