Oh, I have x64 Vista. The trick is to set your Windows locale to Japan- Vista has some trouble with Japanese-named files. The game and patch work fine for me after that, even in Program Files (x86). However, that might be slightly bothersome if you're not ever planning to use Japanese. The GUI is almost the same, but some programs will try to install in Japanese, and all backslashes in file paths will become ¥. There are locale switchers that switch locale for running one program, but I don't know about those.
I'm the opposite from that, though. I'm crap at the older Windows games (save PCB and PoFV), and I could never handle Sakuya. Much better with Sanae. IMO The gameplay was really smoothed out in MoF, I liked it over IN. And I liked MoF over SA, but I like UFO even more. Besides, didn't you BEAT Suwako and Koishi? That's way better than me.