Is this a new install? Check the PC date and time, correct and reboot as needed.
If that isn't it, see this post
for the KB article to troubleshoot install problems - http://social.microsoft.com/forums/en-US/onecareinstallandactivate/thread/ba26b781-da18-4ce4-be8c-22647bd5d8fc/If it is installed, but is simply unresponsive whenever you try to do anything with OneCare, it may be a conflict with other security software on the PC. Norton and McAfee offer cleanup tools to remove all traces of their suites if they did not uninstall cleanly.
Norton Removal Tool - ftp://ftp.symantec.com/public/english_us_canada/removal_tools/Norton_Removal_Tool.exe
McAfee Removal Tool - http://www.majorgeeks.com/McAfee_Consumer_Product_Removal_Tool_d5420.html
If none of that helps, 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
