Small window

Hey everyone, wasn’t sure where to post this question.

I installed Norton anti virus in my computer and since I did this when I am on a site and click to open a new window, the new window that opens is small. I can make it big by clicking maximize, but I never had to do this before, it had always opened as a full window.
I have tried looking in my settings to see if I could find where to fix it, but I do not really know enough about computer and could not find where to fix it.

Thanks for any help you can give me.