You may need this skill to detect hidden viruses in your pen.
For Example lets see how to delete worm/small.2.f (MicrosoftPowerPoint.exe)
1) click Start menu -> run -> type cmd
2) A command Line will be opened.
3) goto your USB drive, type I: (ex: H: or I:)
4) prompt will be changed to you USB driver letter I:\>
5) type dir /a:h and press enter
6) if you see MicrosoftPowerPoint.exe the virus is in your pen drive.
7) delete it by typing del MicrosoftPowerPoint.exe /a:r and press enter.