function EnumWindowsProc(hWnd: HWND; lParam: LPARAM): BOOL; stdcall;
  var
    oForm: TForm1;
    sFormName: array[0..255] of AnsiChar;
    sFormClass: array[0..255] of AnsiChar;
  begin
    oForm := TForm1(Pointer(lParam));
    GetClassName(hWnd, sFormClass, 256);
    GetWindowText(hWnd, sFormName, 256);
    if (
      (StrComp(sFormClass, 'GxWindowClassD3d') = 0)
      and
      (StrComp(sFormName, 'World of Warcraft') = 0)
    ) then begin
      oForm.PushActiveClient(hWnd);
    end;
    Result := BOOL(True);
  end;
 
  procedure TForm1.Button1Click(Sender: TObject);
  begin
    EnumWindows(@EnumWindowsProc, LPARAM(Pointer(Self)));
  end;
 
  procedure TForm1.PushActiveClient(hWnd: HWND);
  begin
    MessageBox(0, 'Found', '', 0);
  end;