If you still have an active subscription, go to
http://onecare.live.com and download/install the trial.
Once installed, click subscribe in OneCare and log in with your subscription LiveID and password. (found in Help/About in OneCare on the PC with the susbcribed copy of OneCare running).
-steve
Microsoft MVP Windows Live / Windows Live OneCare, Live Mesh, & MS Security Essentials Forums Moderator