Why am I receiving 2 notification sounds avery time I receive an email

I have a new Windows 8 laptop. My live mail is set to play a notification sound when I receive an email. Each time I receive an email I get the notification sound at the same time that the email appears on my account, which is what I want and am used to, but also a sound and pop up notification several seconds earlier which is becoming very annoying.
Can anyone suggest what is going on please, and what I can do to stop these superfluous early notifications?