Changing fonts

Will someone tell me how to keep Windows 8 from changing the size of my fonts and web pages?

I keep setting them as large, but then suddenly when I move the mouse, the size gets smaller and smaller for no reason I can figure out.

I turned off "sticky keys" but it's still doing that. And it does this to all three of my web browsers, and now it has started doing it on my desktop.

And yes, I have the font size made large in the "options" box...