Have you got your windows disk? Vista / XP? I'm certain you can do it with vista, all you gotta do is boot the Vista disk up and there's an option to move back to a certain date. - It will reset the whole HD if you do though, to what it was the day you reverted it too.

*sigh*

The odds of System Restore having this stuff is virtually 0 unless you put your LFS folder somewhere silly. You can't "roll" your PC back to a certain time and expect 100 GB of data to magically appear. It is possible to *sometimes* recover data, but your best bet is to do is asap rather than dick around with a system restore.

OT - I know someone that used to wipe a PC, re-install Windows then install file-un-deleters to get their personal data back, and charged people to re-install their OS' :X