Multimedia card protected?

i have a multimedia card is using in my nokia handphone. i cant edit any file in my multimedia card now when i put into card reader, it prompt me a error that “The disk is write-protected Remove the write-protection or use another disk” . anyone help, thanks.

Have a look here: http://en.wikipedia.org/wiki/Secure_Digital_card
If you see the SD card on the right it has a little lever. If you have a lever or some kind of switch on it, you must push it the other way to unlock it so you can modify the files inside the card. Or if you don’t have a lever then you must right click on the file and go to properties and uncheck the box that says “Read Only.” This will enable you to modify the contents on the multimedia card.