In blender i was using numpad to change the view but then i missed and pressed the wrong key(s).Then when i was back to change the view and it just moved my mouse around and the + button which is sopposed to zoom in but nothing happened. 
Now i have to use the mouse to change the view or go to view button and got to view button and click top,bottom,right or left,If you know how to fix this please tell
i think you clicked the num lock button and turn the num lock off. The numlock need to be turn on to use the numpad. 
its on and it still doesn’t work