Ensure there are no other antivirus, antispyware or firewall products installed on your computer. If you have uninstalled an antivirus product, go to the vendor website to see if an uninstall tool is available. If this does not apply or if the ptoblem is not resolved open Internet Explorer and disable all add ons and see if that resolves the issue.
If none of the above helps uninstall One Care, use the cleanup tool - http://forums.microsoft.com/WindowsOneCare/ShowPost.aspx?PostID=828910&SiteID=2 then reinstall One Care. If the problem persists please contact support.