A common way for laptops is to hold down the FN key (next to the CTRL key) and press one of the function keys, most usually F3 or F4 (be careful since one of the F keys puts the laptop to sleep and you may think you have killed your machine but it is a very small problem)
You will see an icon appear on your screen that shows the network is activated. Do the same thing again and the icon appears again but with a red line through it indicating you have switched the network off again. Toggle on and off!
If nothing happens it means the software that activates this keyboard switch has not been loaded (it's a small piece of ASUS software).
I hope this applies in your case.