http://www.symantec.com/goback/
I have this on my son's computer. It basically keeps track of every single file that gets added and modified and you can see a complete list of everything that has been fucked with and revert to any point before you were zapped.
Its a lot like an advanced version of window's restore, but more precise.
The downside is you do see a bit of hard drive performance lag because it is performing so much recording work in the background.