If the OneCare restore utility isn't working on the Win7 PC, I suggest trying a reinstall of the utility first and failing that, contact support.
How to reach support (FAQ) - http://social.microsoft.com/Forums/en-US/onecareinstallandactivate/thread/30400b52-7f26-4ba0-bc18-17e305329d90
I'll also note that you can restore files manually, though it can be painful. Use WinZip or other 3rd party compression/archive program to extract files from the .zip backups. Any large files that were split among multiple .zip files need to be rejoined. You can do that with a free utility after you rename the parts with extensions of .000, .001, .002, etc.
File rejoin utility - http://www.freebyte.com/hjsplit/
-steve
~ Microsoft MVP Windows Live ~ Windows Live OneCare| Live Mesh|MS Security Essentials Forums Moderator ~
