Note: a Windows Live account is now just called a Microsoft account. The account removal link remains the same, however. For the updated instructions, see: http://remove.org/site-item/remove-my-microsoft/
This link is different from the Live/Hotmail removal link, so check what you’re doing. By using this link, your complete account will be removed. If you wish to only terminate the e-mail account, look for Hotmail / Live on this site.
Direct removal link: https://account.live.com/CloseAccount.aspx
Helpful Trick: Removing online data