Something

cls
@echo off

if %1=="" Goto Showmessage

  fsum %1 /V /R
  Goto END

:Showmessage
  echo. 
  echo -= Helper for FastSum easy .md5 files verification =-
  echo.
  echo Do not call it directly! Use it for file associations with .md5 files. 
  echo.
  echo To find out how to associate .md5 files with this Helper please read
  echo users manual for your copy of Windows XP.
  echo.
  echo.
  Goto END

:END
  Pause