What you are describing sounds a lot like the description from the SANS ISC handler about a week ago:

http://isc.sans.org/diary.php?date=2005-09-22

About the only way you are going to get to the Registry and file system and nail these bad boys is to boot from a CD that allows you to edit the hidden registry keys, and the hidden file system stuff. The boot CD I pointed you to will do that. BTDT, got the t-shirt.

Use the ISO to burn a CD and boot to it. Very straightforward.