pen drive files become system files

Symptoms of the Problem:
You had all your data files in the pen drive but when now you connect it to the computer, you find that all the data have been missing from the drive but weird thing about is that when you right click on the drive to see the space utilization, you find that the drive is still showing the space used.
Cause of the problem:
The problem is because all the data that was present inside the pen drive now have the system file attributes that is the files have become system files by the virus. This is the reason why they are not visible even with the option “Show Hidden files and folders”.
Solution to the problem:
To remove the problem this is what you need to do.
1. Go to Folder Options -> View tab
2. Make sure that your Show Hidden files and folders option is enabled.
3. Uncheck the option that reads “Hide protected operating system files (recommended)”
Now when you see your pen drive, you will find that your data is present there but in hidden form. There are 2 ways to unhide the data, either right click and uncheck the Hidden box or type in the following command in the command prompt
attrib filename –h –r –s
where filename is the complete location of the file.