Try rebooting the PC first.
Then start the tune-up again.
If it is asking for your backup device or backup disc, make sure that the backup destination is available.
You can also choose to disable backup - change settings/Backup tab/remove check next to turn on backup for this PC.
If you need help and the above does not resolve the problem, please contact support.
How to reach support (FAQ) - http://social.microsoft.com/Forums/en-US/onecareinstallandactivate/thread/30400b52-7f26-4ba0-bc18-17e305329d90
-steve
~ Microsoft MVP Windows Live ~ Windows Live OneCare| Live Mesh|MS Security Essentials Forums Moderator ~