Just follow the steps as given below :-
1.Click Start, Settings, Control Panel.
2.Within the Control Panel open Accessibility Options or Ease of Access
3.Click the Mouse tab.
4.Check the "Use Mouse Keys" check box.
5.If you wish to increase the speed or change any other settings, click on the Settings button.
6.Click Apply and then close out of the box.
After performing the above steps you will be able to used the numeric keypad as a mouse moving up, down, left, right, and all the diagonals. In addition, you may also use the center "5" key as a left click.
Note: You must have the Number lock on for this feature to work by default. This can be changed through the settings.