Laptop screen settings help please?

My litlle sister has rang me and has a problem with the screen on her laptop! she pressed something by accident and now e thing on screen has gone big! i have tried to get her to chnage the display etc, but nothing has worked? anyone know the answer?
Answer
If you mean using internet explorer, press ctrl and rotate mouse wheel with windows xp or ctrl - (minus) with vista [or ctrl + for larger].