Second screen mode - screen flipped around

Hey there,

my cat was sleeping on the keyboard of my Dell laptop and when she stood up and walked over it she accidentally changed the screen settings and I cannot get it back. So my screen is flipped around everytime I turn on my computer. I manually has to hit `FN` next to the windows button and choose the extended mode with `F1` to flip it back.

Does anybody know how I can make this to the default one so I don`t have to do it every time I log in?

Please help!

Thanks,