Some recipients see weird characters instead of apostrophes and quotes

When I include some characters such as apostrophes and quotes in my emails, some of my recipients get weird characters instead of the apostrophes and quotes that I have typed in and see in the message I have sent.  How do I correct this?  I have tried various mail encoding options and none resolves this problem.  Please help or tell me how to change back from Live Mail to Windows Mail.  By the way, I am using Windows 7.