If your subscription to OneCare shows incorrect or expired in OneCare
- Check your PC date and time.
- Check your subscription status by logging in with your subscription LiveID at http://billing.microsoft.com
- Confirm that this is the same LiveID shown to be the Subscription ID in OneCare - Help/About…
- Open OneCare and click "Check for Updates" to have OneCare check for updated credentials
If your subscription is correctly shown at the Billing site, but incorrect in OneCare and your PC date and time are correct, please contact support.
How to reach support (FAQ) - http://forums.microsoft.com/WindowsOneCare/ShowPost.aspx?PostID=2421771&SiteID=2
I do believe that your issue is the date and time as this would also account for OneCare closing immediately after starting.
What have you tried per the responses from support?
-steve