How to remove your Microsoft Live account
Your Microsoft account will be deactivated for a year, then removed. Within this period you could reactivate it. http://remove.org/site-item/remove-my-microsoft-live/
For closing your complete Microsoft account, there is a different link, see the MSN entry on this site: http://remove.org/site-item/remove-my-microsoft/
Also see: http://windowslivehelp.com/solution.aspx?solutionid=baf3b47e-4618-49e1-ae2c-91e158a4cc76
Direct removal link: http://mail.live.com/mail/CloseAccountConfirmation.aspx
Helpful Trick: Removing online data
Helpful Trick: Remove third-party logins
If you signed up for Microsoft Live using a third-party login such as Facebook or Twitter, you probably want to revoke all access from Microsoft Live. Click here to find out how.