Keypad Num Lock Problem on USB Keyboard

The keypad on my USB keyboard has mysteriously turned from entering numbers to using the numbers as navigational commands. I have no idea why it reverted. I have OS 9.2 and I am using Word:MAC 2001. Now, I know that Microsoft has acknowledged as a problem the fact that SFHT-Num Lock no longer toggles between numbers and navigation. I must have entered some magic combination of keystrokes that toggled instead. I was using the number pad quite happily until yesterday afternoon. Restarting the computer and unplugging the keyboard has not helped.

Would someone please tell me how to get the numbers to turn back on? Thank you very much.

Karen