I am going to say it again (with experience as a Vista user):
I HATE Vista.
Have your friend look under:
C:\Users\YourFriendsVistaUserName\AppData\Local\Vi rtualStore\Program Files\dominions3\savedgames
The above is roughly the path where Vista put mine when I tested an install under Vista
in this post. I have not confirmed my theory, but I suspect that good ol' Vista sees "savedgames" in an installation path and decides to help out by plopping some of the files in one of it's obscure user directories. Gee. Thanks Vista. That will make my life so much easier and certainly more secure. (If it turns out not to be Vista, but some bizarre feature of the Dom3 install program, then I apologize for my sarcasm, but I really believe that it is all Vista.)
Another wonderful feature of Vista is likely the reason that he can't find the folder via the hard drive search. You have to be sure and click the barely noticeable "Advanced Search" arrow and change the location selector from "indexed" to the hard drive and also check the box labeled: "Include non-indexed, hidden, and system files".
Why the hell did they make everything so much harder? Sorry, started to rant again.
Hope that helps!