Why is my screen like this?

Question

my screen is being screwy. if I make the firefox browser maximum size. I can't see half of my screen. I took a look at other questions but they don't help. Please I don't know a thing about computers except for hooking it up

Answer 1

in the bottom corner of the browser there is a magnifying glass that should be 100% if its any more there is the problem click and change it back