It has come to our notice of a ravaging virus that attacks most systems and hides any file
or folder on an infected system or flash drive. If you are affected by this, then here's the help you need. First ascertain that the size of the drive has not changed. Then
follow the following steps.
1 - Open a Windows Explorer...
You can do so by opening "My Computer"
2- in the menu bar at the top of the windows explorer you will find
a "Tools" option.
3- In the tools option click "Folder Options"
4- click on the second tab "View"
5- Select the choice "Show hidden files and folders"
6-Unselect "Hide protected operating system files"
7- Click "Apply", then "Ok"
You should be able to see & open the hidden files on your flash drive

http://www.onegig..com/2013/04/how-to-resolve-hidden-files-on-flash.html?m=1

Good Aftanun Computers gurus, i have an important documents on my flash (usb) , any time i plug it to PC, it says dat " disk is not formatted, do you want to format it now " am not ready to loss dos document , d only back up 4 d document is my usb(flash), pls sm1 shd pls help me out, how can i recover my document without formatting d usb.