[observer23232]

Thanks Razor!

BTW:
im used taskkill for zstdrec.exe

function IsProcessRunning(FileName: String): Boolean;
var
  objSWbemLocator, objSWbemServices: Variant;
begin
  try
    objSWbemLocator:= CreateOleObject('WbemScripting.SWbemLocator');
  except
    ShowExceptionMessage;
    Exit;
  end;
  objSWbemServices:= objSWbemLocator.ConnectServer();
  objSWbemServices.Security_.ImpersonationLevel := 3;
  Result := (objSWbemServices.ExecQuery('SELECT * FROM Win32_Process WHERE Name="' + FileName + '"').Count > 0);
end;

Cancel Button or ISDoneError

var
#ifdef zstdrec
  ResC: Integer;
#endif  
begin
------  
    #ifdef zstdrec
      if IsProcessRunning('zstdrec.exe') then
       Exec(ExpandConstant('{sys}\taskkill.exe'), ' /F /IM zstdrec.exe', '', SW_HIDE, ewWaitUntilTerminated, ResC);
    #endif
end;