My Laptop, No Matter How Hard I Press, Sometimes Doesn't Think I Have Pressed The Key?

have you spilt anything on it? try removing the keyboard and giving it a good clean, then make sure that the wire attatchment on the bottom of the keyboard is connected correctly. if this does not work then perhaps think about buying a new keyboard, you can find them really cheaply on ebay, and they will literally just pop in where your old one was. you may have to remove some plastic cover to get to a screw to release the keyboard, look on youtube for vids on how to remove your laptops keyboard. good luck