The Num Lock key is similar to the Caps Lock key and basically causes the keyboard to use numbers when keys in the numeric key pad are pressed. It works a little differently on laptop keyboards that do not have a separate keypad and keyboards that do have the separate number keypad.
On keyboards with a separate numeric keypad (separate section of the keyboard that looks like a calculator or adding machine or ATM keypad) the Num Lock key, when engaged, causes you to get the characters on the tops of those specialized keys. If the Num Lock key is not engaged, then when you press those keys you get the actions on the bottom of the keys.
On laptop keyboards without a separate number keypad, the number keypad is placed over the letters on the right side of the keyboard. The numbers and other characters are shown on these keys above the letters in a different color, often blue. If the Num Lock key is engaged, then when you press these keys you get what is in the different color above the letter of a number of other characters. On some keyboards some of these keys are scattered across the keyboard. If Num Lock key is not engaged, then you get the normal letters.
On almost all keyboards, there is a light at the top of the keyboard that tells you if Num Lock is engaged. It has a number (one or nine usually) by it. Normally on desktop keyboards you want it engaged and on laptops not engaged.
If you are typing and want letters and are getting numbers or symbols, check the Num Lock key status.
Send your questions to Dwight Watt at email@example.com. He teaches at a technical college in northwest Georgia and does consulting work for businesses and individuals. His website is www.dwightwatt.com.