apostrophe in mail changes form

Using windows 7 and live mail, an apostrophe used in an outgoing mail changes to a series of characters which I can only illustrate by an attachment.
Before sending, the message reads 'I've been'. Having sent it, looking at the message in the 'Sent' folder shows the message already distorted and it is received back in my computer distorted. Attachments in Word arrive in their proper form.
a is file sent
b is when it is received back
Messages from other people are often, but not always, distorted.

Can anyone make sense out of this?

Thanks for the reply. That is a very complicated issue! My problem is a new one after a year of using Live Mail. Can you suggest a route to investigate the change?