Open Device Manager and locate the wifi adapter, right click on it and select Properties. The3n click on the Detials tab and from the dropdown list find "Hardware Ids", will look something like this,
Make note of the "VEN" number and go here,
PCI Vendor and Device Lists
and enter it in the Vendor search box, and it will tell you whether it is the Intel or Atheros. Then download and install the appropriate driver from Asus,
ASUS - Notebooks- ASUS K56CM