espera a que termine shellexecute

procedure ExecuteAndWait(const aCommando: string);


 (...)


//*****************
procedure TForm1.ExecuteAndWait(const aCommando: string);
var
  tmpStartupInfo: TStartupInfo;
  tmpProcessInformation: TProcessInformation;
  tmpProgram: String;
begin
  tmpProgram := trim(aCommando);
  FillChar(tmpStartupInfo, SizeOf(tmpStartupInfo), 0);
  with tmpStartupInfo do
  begin
    cb := SizeOf(TStartupInfo);
    wShowWindow := SW_HIDE;
  end;

  if CreateProcess(nil, pchar(tmpProgram), nil, nil, true, CREATE_NO_WINDOW,
    nil, nil, tmpStartupInfo, tmpProcessInformation) then
  begin
    // loop every 10 ms
    while WaitForSingleObject(tmpProcessInformation.hProcess, 10) > 0 do
    begin
      Application.ProcessMessages;
    end;
    CloseHandle(tmpProcessInformation.hProcess);
    CloseHandle(tmpProcessInformation.hThread);
  end
  else
  begin
    RaiseLastOSError;
  end;
end;

(...)

//**********************************************
procedure TForm1.Button1Click(Sender: TObject);
var
aux: string;
begin

aux:='C:\Users\Pau\Desktop\blat.exe -server smtp.1und1.de -port 587 -f "root@mgflotas.com" -to "informaticoalicante@gmail.com" -subject "AVISO MGFLOTAS " -body "PAU" -u root@mgflotas.com -pw 91919191aA -html';
ExecuteAndWait(aux);

end;