Help! micro SD card problem

Just recently my phone has been coming up with the message on start up that the SD card is Write locked and cannot be written to.
Of course there is no switch on the side of a micro SD card to write lock them, so how do I get around this problem? Looking in the phone settings I cant find anywhere that will allow me to change the setting......Help......!

My suggestion - take it out from ur phone, backup everything, format the card, then restore everything, and try again. If the problem persists, it might be a faulty cad.