If you have an active subscription, which is what was created when you activated originally, you need to use the same LiveID on the subsequent activations.
At this point, are you able to login at http://account.live.com with the original LiveID? If you need the password reset, it can be done from there. If you attempted to activate OneCare with the Hotmail address, the new LiveID, then you will need to reinstall OneCare in order to activate with the correct LiveID for your subscription.
-steve