Originally posted by Jesus I don't see a switch but I will continue to look for something that might resemble one, of I may just buy a new card , that's a better idea , Wally World , here I come !
Hold the card in front of you face up (the "missing corner" will be on the upper right). On the left edge of the card (the actual edge) near the top will be a little plastic thing that slides up & down. It probably even says "Lock" right there with a little down arrow. If the thing is down, the card is locked -- it can be read from but not written to. Slide the thing up, it is unlocked.
Any card you buy is going to be just the same, so best to find that switch.
(And to answer the guy about repeated answers -- I think lots of people read a post and know the answer so they immediately hit "reply" without reading the whole thread. And sometimes people are writing their posts at the same time.)