Hello my name is***** do not rate until we are finished. I look forward to assisting and am very sorry to hear that you are having this problem. Does it show any numbers or anything like that?
Remove the card from the camera, look at the side of it. It should have a tiny lock switch (not all do). Move that switch back and forth a few times. Then leave it on the unlocked side and test it again. Let me know the results either way.
Is the memory card new?