I have two subscriptions to OneCare - one covers my two desktops, one covers my three laptops. Late last week, my Vista desktop and laptop began suffering from the same issue: Windows Security Center reports that I have no firewall or malware protection enabled.
I've tried three different fixes:
http://support.microsoft.com/kb/944175/en-ushttp://social.microsoft.com/forums/en-US/onecarefirewall/thread/c0ca9eb2-14b0-4591-be85-4b7fd1700191/ (two solutions on this page)
I also tried to uninstall and reinstall OneCare. Not one of these solutions fixed the problem; they actually made it worse. Before, I could at least got into OneCare and turn off then turn on the firewall and malware to get Security Center to recognize it again. Now, SC won't even recognize OneCare as an application.
A thread on the second page of this forum speaks directly to this problem. Looks like I need to wait for a fix.