After doing a search on the internet, Deepfreeze appears to be an application that restores your system upon reboot.
http://www.faronics.com/html/deepfreeze.asp
There are 3 ways that I could think of doing this.
First and easiest is just to work from a LiveCD. Garaunteed to bootup the same everytime.
Second is to have 2 partitions of equal size on your computer, then run something like this on boot:
Code:
/usr/bin/rsync -ax --delete-before /mnt/orig_sys/ /mnt/root/
Third, just have your root(/) partition mount as read only.