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How can I map the key to '? Also it's not dirty, I just checkedAssuming it is not a keyboard input issue and the key is set to the wrong one (or indeed none) then you can pop the key and make sure a rock did not get under there which is preventing it (you would usually feel it but you might not) and possibly clean it.
That said when keys start going on laptops I usually find it time to replace the whole keyboard, or work around it (learn the shortcuts if it is just a bit of punctuation, or plug in a USB keyboard/bluetooth keyboard/whatever). Sometimes you can clean them or reseat the whole keyboard but cleaning rarely does much and reseating probably won't do too much here -- if it is going to be the sort of thing it fixes then more than 1 key will usually not be working.

I will take the pics tomorrowWhat model laptop?
Take a pic showing the mechanism of the key.
Chances are it's just a hardware issue if it's not dirty/mechanism isn't damaged. At that point, all you can do is just replace the keyboard. On older laptops this used to be fairly easy, but newer ones you'll likely need to do some work to get the keyboard removed and replaced.