You need to activate the installed trial by clicking Subscribe in OneCare and then signing in with the LiveID used to purchase the subscription or by providing a retail key from inside the retail package. Once you've completed the activation/subscribe process from within OneCare, your copy will be linked to your active subscription. You can repeat this on up to 2 additional PCs. If you ever need to reinstall OneCare, the process is the same - the LiveID is used to activate after install. -steveMicrosoft MVP Windows Live / Windows Live OneCare & Live Mesh Forum Moderator