It's not a direct answer to your question, but you might want to look at
the tutorial at
http://www.bleepingcomputer.com/tutorials/tutorial147.html
Recall that in Vista when you get into the repair dialogs you've got a
WinPE environment, so unlike the XP CMDCONS environment (which was able to
run only character-mode commands) you have many or most of the common
GUI-based maintenance commands such as NOTEPAD available to you under
Vista. From the command prompt you have a PATH variable pointing to
X:\WINDOWS and X:\WINDOWS\SYSTEM32 (X: points to the Vista boot DVD).
Your C: disk is also available (assuming it's not corrupt) but it's not in
the path.
Watch out, though, for commands that assume the local system as their
context -- such as REGEDIT. Open the Registry editor under WinPE and
you're looking at the values associated with the WinPE system, not the one
on the hard disk. ERD Commander (and various other similar products) will
do this, but they're not part of the Windows Vista kit.
A simple summary of the available commands appropriate for the repair-mode
command prompt, and invoked using the familiar command HELP wouldn't have
been a bad idea...but somehow MS didn't bother to include it.
Joe Morris