First, check the PC date and time by right clicking the clock in the system tray. If the date/time is incorrect, fix it and reboot the PC. If that doesn't resolve it, try the Virus and Spyware repair tool - http://forums.microsoft.com/WindowsOneCare/ShowPost.aspx?PostID=2667445&SiteID=2
And, finally, if the problem persists, please contact support.
How to reach support (FAQ) - http://forums.microsoft.com/WindowsOneCare/ShowPost.aspx?PostID=2421771&SiteID=2
-steve