function GetFileVersion(const fn: String): String;
var
  tmp, InfoSize, FileInfoSize: DWord;
  Info: Pointer;
  FileInfo: PVSFixedFileInfo;
  function IntToStr(i: Integer): String; begin Str(i, result) end;
begin
  result:='';
  FileInfo:=nil;
  InfoSize:=GetFileVersionInfoSize(pChar(fn), tmp);
  if InfoSize = 0 then Exit;
  GetMem(Info, InfoSize);
  GetFileVersionInfo(pChar(fn), 0, InfoSize, Info);
  VerQueryValue(Info, '\', Pointer(FileInfo), FileInfoSize);
  with FileInfo^ do
    result:=inttostr(dwProductVersionMS shr 16)     +'.'
            +inttostr(dwProductVersionMS and $FFFF) +'.'
            +inttostr(dwProductVersionLS shr 16)    +'.'
            +inttostr(dwProductVersionLS and $FFFF);
  FreeMem(Info, InfoSize);
end;

procedure TForm1.Button4Click(Sender: TObject);
var a:string;
begin
showmessage(GetFileVersion('Arquivo.exe'));