I have seen such a case when one my friend forgot the password of his Memory Card of his mobile phone and he have some very important data in the memory card which he want to recover, he tried almost everything then he lost hope and then asked the mobile phone company to find the way to recover the data from the memory card.
But you dont worry if you are having the same problem as now there is a much simple and easy way out.

Requirement: You need a file explorer like FExplorer which you can download from here.
How to Unlock MMC card:

Method 1:

1.Insert card into your phone but dont access it through phone.

2.Run FExplorer and Open the path C:\system.

3.You will find a file called mmcstore ,rename the file mmcstore.txt

4.Copy that file(mmcstore.txt) to your pc and open that file in notepad.

5.You will find your password in that file.


Method 2:
Applicable to all nokia phones which are s60 2nd or s60 3rd edition series phones.check out here.
If you still have any problem in finding your password for your memory card ,leave a comment here.