function ScreenSaverEnabled: Boolean;
 var
 status: Bool;
 begin
 SystemParametersInfo(SPI_GETSCREENSAVEACTIVE, 0, @status, 0);
 Result := status = True;
 end;

 procedure TForm1.Button1Click(Sender: TObject);
 begin
 if ScreenSaverEnabled then
 Caption := 'Screensaver is enabled.'
 else
 Caption := 'Screensaver is disabled.'
 end;