How do I reprogram the keypad keys on a keyboard?

In short, how can I design a program to accept Numlock Off key 3 and give a $ for example?
Numlock ON 3 should still deliver a 3.

Also, how might I have numlock OFF and have the <enter> key deliver text ABCD?

I have looked at SharpKey but apparently it will not do this.  I started to look at other programs but cannot get anyone to show me that it will work.  (AutoHotKey, KeyTweak)

Everything I know I learned from my cat. No matter what the situation is, there is a napp for that.