One Care is nearing end of life and retail product keys are no longer being accepted. You may be eligible for a refund. See this post for information and options -
http://social.microsoft.com/Forums/en-US/onecareinstallandactivate/thread/0000c782-ed1b-4ed3-8afb-87989bb9638c
Jim
Microsoft MVP Consumer Security - Forum Moderator - Live One Care - Live Mesh - Microsoft Security Essentials