Taken from: mrjuandeluca

This has been reported in helpdesk. The OS has been zoomed in with no visual indication on how to zoom out. Note, this is different than zooming in a browser window.

You can press Ctrl + Alt + Brightness up or Brightness down, or (my preferred method) use Ctrl + Alt + two fingers scrolling up or down on the trackpad to magnify the screen. Have the user zoom out to the default, then turn this setting off if it is problematic.

Scroll down a little...

That's it!