Memory card and USB memory stick problem

Help with the memory card of my Digital Camera and my Flash disk.
folders do not display when i connect my card to my computer. I need to use 7-zip to be able to view the folder "DCIM" which stores photos in my memory card, else they are completely invisible. What do i use permanently remove that which causes this effect. the same virus or whatever converts all folders in my flash disk to shortcuts which never open anything. Help on this issue. the memory card in my mobile phone is also affected in the same way.
Help!!