Clive25,
Thank you for visiting the Live OneCare program forum.
To resolve this problem, you must use the Windows Live ID that you originally used to install OneCare when you activate the new instance of Windows Live OneCare.
Here is a great link for you to reference regarding the 8059 error message.
KB944173 - Error message 8059 when you try to activate Windows Live OneCare: "The Product key entered is already in use. "
http://support.microsoft.com/kb/944173
Thank you for visiting the Live OneCare program forum.
Rick, MS