HI!
Go to onecare.live.com, click on the free trial to install Windows live onecare. After installing, associate it with your subscription by signing in with the live id and password that you have used when you subscribe to it to make it a full version.
Choose HOME OR WORK for the firewall zone location.
for more help Contact support : How to reach support -
http://social.microsoft.com/Forums/en-US/onecareinstallandactivate/thread/30400b52-7f26-4ba0-bc18-17e305329d90Additional reminders: You can install or use your subscription for up to 3 computers...Vista and XP computers only.
----- bayabasgirl29