Hi, you didnt say what memory card format it is but I'm gonna take a guess at SD
I had this happen to one of mine for a PDA and couldnt save anything to it so what I had to do was cut a small piece of plastic (I used a bit from a toy of my kids lol) and superglue it where the slider should be when its unlocked (google one if you are not sure or if you have a spare copy that)
Make sure you give ample time for the glue to dry do you dont glue it into your camera!!
that should do it
Hope it works
Ekips
January 2008