How to remove memory card password

find your memory card's forgotten password by following these steps: 
Download and Install FExplorer. 
Insert card into your s60 1st or 2nd edition phone but don't access it through phone. 
Run FExplorer and Open the path C:\system. 
You will find there a file named mmcstore , move this file to other location of your phone, rename the filemmcstore.txt 
Open the file in your phone or Copy that file(mmcstore.txt) to your pc and open that file in notepad.
You will find your password in that file.
By this way, you can unlock memory card and recover your memory card's password.

or

Insert your locked memory card in phone.
Open the memory card options. You will see an option of format, select the format option. After formatting, you can at-least recover your memory card to reuse.