Hidden folders in pen drive-because of virus attack- Folder name .exe Virus -solution

Folders in pendrive were changed to hidden by virus attack, unable to change to visible as the hidden tick box in the properties of folder is grayed. If you insert the pendrive into the system, the folders are not displayed.   The solution to this problem is 

Take start Menu ->Run->cmd 

Type the following command  

attrib -h -r -s /s /d h:\*.*      

In place of h:   type the  drive name of pendrive.