Go get NTPASSWD and it has an offline registry editor. You can also use the microsoft KB article about loading the hive and editing it there. As you must be a guru I'll point what direction to go but stop short of a step by step.
The good news is their files are likely fine. Just pop in a new blank drive, reload and copy their files from the old drive then issue the bill for the work.
Customer changed environmental variables value by clicking on my computer, properties, advanced, environmental variables, edit (user variables), and changed Variable value to the word "windows".
Now windows gives us a blue screen and does not load from any other mode, not even from safe mode.
I tried to boot from CD in order to perform a recovery but it gives me a blue screen (pci.sys error).
I can read the hard drive on another PC, no problems.
I was wondering how to change the environmental variables back to what it was.
Thanks in advance.