Close your account
When you close your account you permanently delete your registered information (This is information given to Windows Live, including your e-mail address and password.) and credentials (Unique information that you use to access restricted resources. For Windows Live, credentials include your e-mail address and password. They may also include a mobile phone number and PIN, a smart card, or a security key.) , as well as your Messenger contact list and Windows Live contacts. You'll be unable to sign in to any Windows Live sites or services.
To close your Windows Live account:
Go to the Account Summary page.
On the navigation bar, click Settings.
Under Common tasks, click Close your account.
Verify that the correct Windows Live ID user name appears, type your password, and then click Yes.
If you manage a child's account, the child's account permissions will be revoked if you close your account.
If the account you close is associated with any premium services (These are paid subscription based services such as Live Mail Plus that require you to establish a billing relationship with Microsoft) or with a Windows Live Mail inbox, you must cancel the subscription to each service or close your Windows Live Mail account before you close your Windows Live ID account.
Some of your information will not be deleted. To learn more about this see Microsoft Online Privacy Notice Highlights.