U have not locked ur card reader, u have locked ur mmc card. To reset ur MMc password insert ur card in ur mobile phone and follow these steps:

Go to the file manager on your phone, in the "Settings" option

, choose to see the system folders, In the "System" folder

on the phone there's a file called "MMCSTORE", send that to your PC using IR/Bluetooth,

then open it in notepad. The password you need for your memory card is in that file

Thanks