Since you have already posted the email address (which only Support can see) MSN Support may be able to assist you via this forum.
The issue is the same for Hotmail (free) users as compromised accounts have been disabled and require action to regain access. Below is the reset information for free Hotmail users and some other useful links.
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
-steve