windows 7 - Issue with Num Pad

I have a problem with my Num. Lock key on my Toshiba Satellite C650. In fact, when I start up my computer the Num. Lock. button works fine, I can use it to activate the num pad and I even can type my password using the num pad but after authentication the num pad is automatically disabled and I can't activate it anymore, Num. Lock. seems to be useless once I get authenticated. I tried to change the Value of the Keybord Registry Key and uncheck Turn on mouse keys but this didn't solve the problem. I'm working on Windows 7 x64. Any help would be appreciated.

Update: num pad buttons work fine but not as numbers i.e: when I press 4 the cursor moves to the left. The problem is that I can't turn on the Num. Lock

Answer

Use Win7 built-in "On Screen Keyboard" to test if NumLock behaves well.

1. Press +R




2. Enter osk




3. In bottom right corner, click "Option" and checked the Number Panel
   boxes




4. Press NumLock