I am running Ubuntu 9, and recently I have a very strange error.
My number pad on my keyboard don't work. Its not hardware since I changed the keyboard and I still have the same problem.
It could be your mouse settings. Your keyboard is set to move the cursor with your number pad.
To Slove this issue
Check if the mouse pointer moves, when you press 4 on the numeric pad? If so your keyboard are in the incredibly annoying mouse keys state.
[shift]+[num lock] dosen't work for me on ubuntu 14.10