Nikon colorpic s50 memorycard problem

my nikon coolpic s50 is having problems... when we have a memory card in it a error comes up that says "memory card is write protected" and if you look that problem up they say its a problem with the memory card and to slide the write protect to unlock.... but on mine it is un locked... we even bout a new memory card thinking that was it but even after we got the new memory card that error is still coming up with the new memory card and we cant find any way to fix it yet... any suggestions????