FYI, the problem stems from loading the incorrect 'keyboard language' at start-up. The keyboard language determines what instructions the computer receives as you type individual keys. In other words, if you see " instead of the expected @, the computer is behaving in accord with the default 'keyboard language'.
Hold down the alt gr key on the right of the space bar and tap 2 key. Using the alt button on the left of the space bar doesn't work. Really weird keyboard on Acer. I asked this question on the "experts" forum a couple of months ago and they couldn't help me, nothing worked. Tonight a techie friend discovered the answer by accident.