If you cannot reset the password through the usual means, see this page for information on how to get help with it:

http://windowslivehelp.com/solution.aspx?solutionid=bf5d34bf-db28-44ca-ac9a-93838d81b2d6

There is a form to use that Support will act on, but it can take more than a day for them to deal with it. Be sure to enter both the account you cannot access and another account where they can reach you. Once you regain access to the account be sure to set an alternate email address and secret questions and answers for account security at http://account.live.com/

You may also want to review these posts:

https://windowslivehelp.com/solution.aspx?solutionid=6ea0c7b3-1473-4176-b03f-145b951dcb41

https://windowslivehelp.com/solution.aspx?solutionid=91b88c76-30ec-4879-9c72-0dd425a5b5f3

And also these blog entries from the Windows Live team:

http://windowsteamblog.com/windows_live/b/windowslive/archive/2010/09/27/hotmail-security-updates-protect-you-from-account-hijackers.aspx

http://windowslivewire.spaces.live.com/blog/cns!2F7EB29B42641D59!42740.entry

Also see the information here:

https://windowslivehelp.com/solutions.aspx?categoryid=03d16037-31cc-48e5-9214-cef9e4aa34ce