For those who has probs with "damaged" SD card, try this prog: H2testw, Download bei heise
Connect your SD to PC and Run the prog:
(NOTE: I'd recommend to format your SD before using this program, backup all your data!)
1) language - switch to "English" (if you want)
2) "Select Target" - select your SD here
3) "Data volume" - all available space (selected by default)
4) click on "Write + verify"
5) wait. Once it's complete, delete temp file that was created on your card.
If you see this, something is wrong with your card: