How do i fix a blurred screen, oversized icon

Hello,
hi there am having issues with my computer scrren and enlarge icons .. there is no way i can fix the settings
because the icon is so huge .. no way i can scroll down to press ok .. to resolve the issue at hand
cant press f8 it is not comming up when i press it . cannot go into run and press system restore .. that does not work .. please need your help