Below my LCD, there is a row of indicator lights and now there is a triangular or arrow shaped one with a "1" in it that is now illuminated. Everything seems to be normal, but if I press the U, I, O, J, K, L, M buttons, I get numbers displayed. What is this?
This is the indicator for the "num lock" function and means that num lock is enabled. When enabled, some of the keys on the keyboard are mapped to provide a numeric keypad layout function for those who are used to a dedicated keypad. In the diagram below , Item #6 is the numlock indicator, and #7 is the caps lock indicator.
Depending on particular model, a Fn + or Ctrl + numlock key will toggle this function on / off