The issue is that you have reinstalled and activated with the same LiveID as an existing subscription, so it inherited the status based on your LiveID. You did not need to uninstall or reinstall, you simply needed to renew with the key - which you can still do now:
Go to http://billing.microsoft.com and sign in with your subscription LiveID. (Open OneCare and click help/about to view the subscription LiveID)
Select the OneCare subscription and click on the renew link.
Choose the option to renew with a prepaid PIN or token which is the retail product key.
Enter the 25 character key and proceed.
It can take up to 24 hours for the subscription status to be updated in OneCare.
-steve