var
  QuellDatei, ZielDatei: String;

  FileLength: LongInt;
  FromF, ToF: file of byte;
  Buffer: array[0..51200] of char;
  NumRead, PB_Position: integer;
  S: String;

begin
{ ... }
  AssignFile(FromF, QuellDatei);
  FileMode := fmOpenread;
  reset(FromF);
  AssignFile(ToF, ZielDatei);
  rewrite(ToF);
  FileLength := FileSize(FromF);

  try
    //Variablen vordefinieren (Progressbar)
    PB_Min := 0;
    PB_Max := FileLength;
    PB_Position := 0;

    while FileLength > 0 do
      begin
        BlockRead(FromF, Buffer[0], SizeOf(Buffer), NumRead);
        FileLength := FileLength - NumRead;

        BlockWrite(ToF, Buffer[0], NumRead);

        //ProgressBar
        PB_Position := PB_Position + NumRead;
      end;
  finally
    CloseFile(FromF);
    CloseFile(ToF);
  end;
{ ... }