Windows laptop homepage screen has moved to the right

Registration date
Saturday June 24, 2017
Last seen
June 24, 2017
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.