Open OneCare to see what the reason for being at risk is and follow the provided instructions.
If you are unable to resolve it, please contact support.
How to reach support (FAQ) -
http://social.microsoft.com/Forums/en-US/onecareinstallandactivate/thread/30400b52-7f26-4ba0-bc18-17e305329d90
-steve
~ Microsoft MVP Windows Live ~ Windows Live OneCare| Live Mesh|MS Security Essentials Forums Moderator ~