This is a quick-tip for some that suddenly cannot use mouse to move cursor and need a replacement to continue working on the screen.

This just is a key combination,press left-Alt + left-Shift + NumLock.
This enable the Mousekeys,so you can use number keys in nubmer pad to move the cursor just like using the mouse.Use “5” and “Enter” key to open something.
To disable this Mousekeys,just press the key combination again.

I found this stupid tip in Ubuntu and I guess it works in all other systems