Check Windows Control Panel, System, Hardware, Device Manager and see if the device is present or yellow flagged as faulty. If it is flagged, uninstall it and Refresh. It may reinsatll correctly. The other thing that can happen is that the hardware has failed or that you have some driver issues. Go to the Emachine website and download the drivers for your laptop and reinstall those.Good Luck and let us know how it is going.
Some laptops had the switch on the side, Most now use a function button..Look for the button on the keyboard with the wifi antenna icon on it "usually on the top row of buttons". Press that button and the FN button at the same time...This will turn your wifi on and off. The wifi button on most laptops will be lit when wifi is on.