How to make @ key work? Have bought Mac air 11 inch today. Cannot make @ key function. I Have pressed alt and the @ key together.  Nothing happens. It seems that other signs on the right side are not the same as what I see on the screen. For example, if I press ?, it gives me -.  Is something wrong/broken?
Maybe your keyboard does not match the settings in your System Preferences. It would be good to include the layout of your keyboard i.e. English UK, English US, or maybe another language's default.

To check your System Preferences setup go: System Preferences --> Keyboard --> Input Sources. There you will find which button layout is set.

By matching that to your actual keyboard layout you may be successful resolving your issue.