I purchased a surface book about 7 months ago and for about the last two months, the Fn key has stopped working the way it should. Currently the light stays off and only comes on when the button is pressed and goes off when the button is released (it doesn't
stay on). Normally when the button is pressed, the light should go on the when it is pressed again, the button should go off, this is not the case. At the moment the F1-F12 keys perform their normal functions i.e. refresh, etc and not the other functions when
the light is on such as volume up, volume down, mute, play/pause, home, PgUp, PgDn, etc.
So my question is, how do I get the Fn button back to functioning normally where the light comes on when the button is pressed and goes off when it is pressed again (F1-F12 functions when the light is off and volume, PgUp, PgDn etc. functions when the light
is on)?