I'm sorry that I'm not clear on what your problem is.
If you reinstalled OneCare on the PC after the crash - assuming that you had to fix Windows by restoring or reinstallin - did you activate OneCare by clicking Subscribe and then signing in with your subscription LiveID to get hooked back up to your subscription?
If you did and you mean that it now will not update:
Information to help troubleshoot and resolve update problems -
http://social.microsoft.com/forums/en-US/onecareupdate/thread/9a6a0003-b91c-4518-966c-fc50450f0e41/
If you need help, please explain more about your issue or 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 Forum Moderator
