I have a problem

While I'm playing I'm hitting a button that makes me unable to use spells and my left click (i have set to attack command or whatever its called) just spams pings. I'm not sure if its the Windows key or the FN key. I've had this problem here and there but the past 3 games i've had it happen so I need to either figure out a way to disable the keys or something. Any thoughts or ideas would be appreciated