Many times pen drive gets infected by following files for Windows XP

 Autorun.inf
 folder.exe
 Iexplorer.vbs
 Bha.vbs
 nfo.exe
 New_Folder.exe
 ravmon.exe
 RVHost.exe
 any other files with extension.

just follow this steps :
Step1.:Type cmd in Run
Step2.: Switch to the drive on which pen drive is connected (like C:\> h: enter)
Step3.: type exactly as attrib -s -h *.* /s /d and hit enter (don't forget spaces).

I hope u all like this post

Thank You