@artiststudio
It is possible that the server that hosts your account has undergone maintenance. If you’re still unable to access your account please read What to do if you can't sign into Windows Live Hotmail found at:
http://windowslivehelp.com/solutions/servicemgt/archive/2008/12/26/what-to-do-if-you-can-t-sign-into-windows-live-hotmail.aspx
If the issue persists, please post your e-mail address so we can investigate.