how to move the mouse pointer without scrolling the screen?

Not sure what you mean. If you just move the mouse without dragging a finger(s) on it's surface it will move the cursor. The screen itself shouldn't scroll in any case unless you have zoomed it.

I know what you mean. I could use the mouse the first time I tried but some of my clients can't get the hang of it. You have to coordinate your movements. I bite my lip if I try to chew gum and walk. Likewise, the magic mouse is either for you or not. You might try going to the mouse pane in system preferences (the gear wheel icon) and unticking Natural Scroll direction. It might help.