Why when you use a pen on your laptops touchpad it doesnt input it on the screen but when you use your fingers it works im trying to use it as a graphics tablet?

Edit

I have a Toshiba Satellite with Windows 8.1.As I turned it on everything was OK but after a minute or so my touchpad stopped working,it doesn't move it will scroll and click but without the cursor moving.I figured that it actually works but I have to double tap the touchpad and then move but after I stop it won't work again and I have to double tap it every time to move it and it makes things very hard.I tried restarting it and turning it off and then on again and just after it goes on the touchpad works fine but again after a moment it stops.What should I do?

Update: I also tried disabling and then enabling it but it doesn't work.