Normally you can view hidden files by clicking
Folder Options -->
Show Hidden Files and Folders
But this simple method doesn't work when your pen drive is attacked by harmful viruses.
So here I'll provide you an easiest method to view your infected files from pen drive without using any software.
Insert pen drive into computer and find drive letter of connected USB drive
For Example, E:
Now click on Start --> Run
In Run box, type cmd and hit Enter
Now command prompt will appear, in command prompt type the drive letter of your pen drive and hit Enter.
Example type E:
After that, type attrib -s -h /s /d *.*