Project window too big

So I have a project that I worked on in school. and when I run my project it at home, the project window run partially off-screen. 

The window is supposed to be 1600 * 900 pixels but it is way bigger than that. 

my monitor has a resolution of 1920 * 1080 .

Is there a way to change this?

(I'm also fairly new to this so please don't go in too much detail)