FTYPE

1) To display a list of current file type open strings, type ftype at the
   command prompt, and then press ENTER.
2) The command ftype exefile returns
      exefile="%1 %*
   which corresponds to the contents for the key:
      HKEY_CLASSES_ROOT\exefile\shell\open\command
   This tells the system that the file with the .exe extension will be run
   will all agrguments available at the command line. Some malware changes
   this so that the malware is executed each time an executable file is
   launched. The administrator can fix this by typing the command:
      ftype exefile="%1" %*