Look in device manager to find what wireless chipset you have (Azureware, Intel, Atheros or WiMax), go to the website page
https
/www.asus.com/us/Notebooks/K53E/HelpDesk_Download/
select OS then the wireless, then the latest driver for your chipset.
Also, make sure the wifi device is not turned off in the Windows or disabled through any buttons on the keyboard.