Windows 7 "Guest mode" implementation?

Question

Windows 7 beta had a feature called "Guest Mode", based on SteadyState or PC Safeguard that was available for Win XP and Vista. SteadyState was perfect! But for some reason discontinued support for Windows 7.
How can I implement something similar in Windows 7? Closest I can think of is parental control, I could limit what the users can do, but I cannot prevent them from altering files. At the same time I want them to be able to use the files, and the programs needed will need read-write access.
How can I make the changes a user makes to the user's profile and files temporary per login session?
Any help appreciated,
Thanks.

Answer 1

Here is how to do it using tools available from Microsoft.

I haven't downloaded or read it yet, so I can't comment on how useful it is.