If that doesn’t work try remembering when the last time everything worked the way you wanted it to, and go into system restore and restore the laptop to a previous date when it worked the way you wanted it to. If this doesn’t work then try updating the laptop’s keyboard drivers. The function key enables the ability to change the brightness settings, the volume, enable numbers lock and disable Wi-Fi among other things. Make sure that the function key is not on when you are pressing the shift key (or the 4). I have seen anything from blue to aquamarine to red to orange to brown to black when the keys are on a pink laptop and the letters are white.
See what the colors on the rest of the keyboard are, the function button is usually a different color than the rest of the keyboard letters and numbers are. First, check to see the color of the letters on the function button, which usually are Fn or FN.
As a tech person I get asked questions like this all the time.
