I've moved your post to the Install and Activate topic in the forum.
If you have OneCare installed on your laptop, open OneCare and click on Help/About to see the LiveID for your subscription. You can reset the password at http://account.live.com or contact support if you continue to have problems logging in with your account,
You will need the LiveID to activate the subscription on the other computer.
You can disable backup in OneCare, but that is not the same backup that the store made for you. OneCare will backup your data files - documents, picture, etc, per your plan settings. Click on the backup option/warning to configure (or disable) backup.
You can choose to make either, neither, or both the laptop and desktop PC into a Hub in your Circle. That's up to you.
-steve
