Как проверить, включён ли ActiveDesktop.

function IsActiveDeskTopOn: Boolean; 
var 
  h: hWnd; 
begin 
  h := FindWindow('Progman', nil); 
  h := FindWindowEx(h, 0, 
	     'SHELLDLL_DefView', nil); 
  h := FindWindowEx(h, 0, 
       'Internet Explorer_Server', nil); 
  Result := h <> 0; 
end;