I'm guessing you've downgraded to Windows 7 from Windows 8 or Windows 10 - - right?
Well you'll be disappointed to learn that Asus doesn't support Windows 7 on the X553M/MA series. - - they never released any Windows 7 drivers for it which is why the network adapters don't work.
https://www.asus.com/support/Download/3/627/0/1/E2zW85Fa0kh9QOb3/41/
You are supposed to check what drivers have been released before downgrading or upgrading the pre-installed OS.
You must restore the factory pre-installed OS, then the problem will be fixed.