Sounds like your laptop is set to have the FN function of those keys on by default, which allows you to adjust sound volumne, mute, turn wifi on and off, and such just by pressing a single button. To access the F-key (F1, F2, and F3 which is what you want here) press the key with the blue FN on it, normally located in the bottom left between the Control and Alt keys. Then press F3 and it should send the actual key F3 instead of whatever the special function is, wifi on/off in your case.
Most new laptops are setup this way. There is a setting you can change to reverse the behaviour so that you need to push the FN key first to get the special functions of those buttons, but you might find that annoying for stuff like volumne up/down and such.