It is your Windows Live ID that you need to get back.
1. Go to click here
2. Click any topic at the left side of the page
3. Click "Get more help" located at the bottom right part of the page
4. Click "Get support."
<you get a form to fill in>
Provide your Windows Live ID sign-in information or personal e-mail address.
* *Full name:
*The e-mail address for us to send a response:
*Primary e-mail address/member ID associated with the account you are inquiring about:
So that we may better assist you, please provide as many details as possible about your issue.
<(- and more boxes to fill in.)>