Windows laptop homepage screen has moved to the right

My keyboard just goes nuts sometimes. Changes font size in the middle of typing, and sometimes changes itself back! The problem I really need help with today is that my homepage screen has moved to the right of the screen where the right of the page is crammed off the page and I cannot access it or get it to re-center. I may have accidentally clicked the mouse but don't know what I would have hit to do this. it was just gone in a flash. I can't access anything on the right hand side of the page. How do I reset it? I have searched for a tutorial on keyboarding but they do not seem to answer my problems.