I have an old Starforce riddled copy of SH3 working just fine on 64-bit Win7. All I can say is that I followed the instructions stickied somewhere hereabouts, and if I remember the most important bits are don't install in the defaulted Program Files (see below), don't install GameShadow, and don't click finish when it asks. I've only had to install the once on W7, unlike XP.
Oh, if you're quite good keeping your security up, and are the only user I'd recommend disabling UAC (if you do disable then installing in the defaulted Program Files shouldn't be an issue).
Good luck, let us know if (when) you get it working.
