But After reading a lot of forums, and tried a lot of things, I found another solution.
I put my memory card into a memory card reader and connected it to my pc. Even my pc didnt recognize my memory card.. it had an error. so I couldnt even do a back up.. So I clicked right click on My Computer, then manage> Disk management> right click on my card, And then format. I didnt wanted to loose my data so I downloaded "Recuva" and I choosed what things I wanted to recover (after the successful format FAT32, which also made my SD card visible)
And so my sd card was visible again and I recovered whatever I wanted.
Hope I helped... But please do this at your own risk!
Sorry for bad english