touch pad woes elements 3

I have been tryiing to work with the magnetic lasso. I am using a lap top with a touch pad for placement of the cursor. It is a Toshiba Satalite 1000. Here is waht happens. all is going well and then the lasso takes off and moves either to one of four maximums ie right, left, top or bottom. It goes right past the photo and forces the photo in the oppite direction. So if the MLasso is shooting toward the bottom the photo ends going so far up it is just about visable. I tried just about all the setting for the wand and then moved to all the setting I could find for the touch pad. Nothing seemed to work. If I used a mouse would I override this or if I used a drawing pad could I get past this problem? It seems to be a sensitivity in the touch pad that I do not understand. Any help is appreciated. Computer almost ened up in the drink last night after many adjustments and many failed tries.
Thanks again
John