I have to test this, I guess if it can boot at all it can fix things up.
Comodo Time Machine
"Comodo Time Machine (CTM) is a powerful system rollback utility that allows
users to quickly restore their computers to an earlier point in time. CTM
'snapshots' are a complete record of your entire system (including the registry,
critical operating system files and user created documents).
"Software Developers and testers can easily restore test systems to the default
configuration after each deployment without the need to manually uninstall each
application. Home users can even let the kids run amok on the family PC for an
afternoon and be safe in the knowledge that any damage can be instantly
undone and all files recovered."
Comodo's Product PageThump