Stop the zoom action from changing at free will

I NEED to know, how do I stop the zoom action from changing at free will when I scroll around on the screen or page?
I have changed the zoom setting without any luck. I have changed the settings per page without any difference. I do not have a scroll lock button but I am taking suggestions and solutions.
This has been happening for a long time now and it's about to make me lose my mind. If you can imagine how long it takes me to do anything on my computer you would understand why it's so important why I get this fixed FAST! I will be waiting and watching for a solution for this problem. ANY TAKERS?

I AM A GRANDMOTHER.