Every email message includes a block of text at the top that is referred to as the header. The header contains details about the message, including the sender's information, the recipient's information, the servers that handled the message as it traveled from the sender to the recipient, etc.
To view the headers of an email message in Windows Live Mail, while in your Inbox, right-click the message and click Properties. At the top of the box that appears click the Details tab. The email message header will now be visible to you.