I have the same problem, I used my memory card with a memory card reader in a public computer of a touristic place in Mexico - all my pictures disappeared. I can view my pictures in my camera, but once it's connected to a PC, my pictures just wouldn't show at all ( as if my memory card was empty, however under the properties I can see that the 8GB memory card is almost full).
When I got home I noticed that there is a new folder created on the memory card called "recycling" and an exe file on it. My AVG immediately spotted a Trojan and removed it in a sec. The trouble is that even though the card is virus free now I still can't access the pictures on the card - almost 7GB worth!
Some of you said that a virus might hide the photos and it's possible to unhide them. How is that possible? I am a bit scared to format the whole thing and use a data recovery software, I would rather do this as a last resort.
Any suggestions?
Thanks a lot.
Judit