I deliberately have my system configured so that it has the OS on a disk by itself. And, my final config isn't much different from the default install. Requires less than 5 minutes to get it to that state after a fresh install. So, it was easy enough to go that route.
Thanks for the tip though ... I'll try it should I run into the situation again.
I think your problem was in corrupted manifest repository.
Due power failure you have inconsistent filesystem, and need to restore one of your backup manifest. Try to look at documentation on service and failure facility.