However, Windows Live OneCare is at end of life. If you do not have an active subscription, you will not be able to activate OneCare. If you have an active subscription, it cannot be renewed when it ends.
See this post
for End of Life information for Windows Live OneCare - http://social.microsoft.com/Forums/en-US/onecaregeneral/thread/81996436-edad-41ba-bdfc-02fc094e2ca9
download and install the free Microsoft Security essentials for malware protection -
If you used OneCare for backups, you'll still be able to restore from old backups if you use the OneCare Restore tool -
but you'll need to seek an alternative backup solution.