On your memory card there is a little switch on the side click it the oppisite way you have it and it should unlock the memory card
lock and unlock you want to unlock it
Card locked and mean the card protection device has been activated. Have you indadvertantly activaded the device? This is usually a button with the 'Key' symbol or can be through the menu on screen. Check your manual If this does not resolve it put you problem to the Tech Support Team at Canon
Usually answered in minutes!