A lock picture on folders from a possibly virus infected memory card

I have 3 folders on my portable HD that have locked symbols on them, they aren't locked though, as in I can access the folders and all it's contents. I'm worried it means the folders are infected with the virus my computer had before I started using ubuntu.
Out of the three folders, two of them are very important to me, my pictures folder and my music.

What can I do about it?
What does it mean?