ITT: People who don't know how to use Vista and complain when something goes wrong.
On a side note. The only reason I can think of Vista doing something of this nature is due to an installation of the game from a burnt copy. Yours was a legal copy, correct? If so, then it's most likely that when it was updating the key registry to recognize the game, an error occurred or a file was copied badly due to some defect/filth from the disc and had to restore from it's last known point of restoration backup. So it might have been your disc more than Vista.
I don't mind system restore even on random occasions. It still keeps all the files I've downloaded (unlike XP) and I can always reinstall anything that was removed via a folder I keep in just such instances in my documents folder.
I hope that was somewhat helpful as far as what might have happened and how to keep it from being as painful in the future.
