Num lock

The computer is an IBM Pentium II, 350 mghz.
I removed the the original HD and replaced it with a 80gb Maxtor. Next I formated the new HD and reloaded Windos 98. Everything works great except the keypad on the right side of the keyboard. The bios setting is set to enable num lock at start-up
and after the computer and Windows 98 is started the NumLock light is on but the only key that works is the enter key. I asked this question earlier, but it was somehow closed before I received an answer to th problem. I have discovered since I first ask the question that when I turn Num Lock off (Num Lock light off), the keys all work. How do correct the problem to make it work as it should?