My email screen has suddenly become magnified.?

Hold down the CTRL key and slowly tap the minus - or plus + key to increase or decrease

OR

Hold down the CTRL key and slowly turn the wheel of your mouse. One way increases, the other decreases

( dont let up on the CTRL key until you reach the desired size)

at the bottom right of your screen just above the task bar you should see a + sign in a small magnifying glass - and this should read 100%, if it doesn't, just click on the small arrow and this will give you a list of the zoom in and out percentages, put it back to 100% hope this helps