Well I haven't use XP in years. Going back isn't and option. Win7 or vista x64 doen't work with starforce...
SH3 alone does work.. Starforce is blocking access.. I've even check SF site.
http://www.star-force.com/support/users/windows7/
There are some help there but it don't work. They're drivers only support win7 beta. Not RC-1 or RTM. So your out of luck.
Other option is doing the alt method but I won't say that here.
To buy SH3 again? Isn't going to happen! Sorry I already payed for the game.
So I'll leave it up to you honest owners what to do to fix your game..
If you need help send me a PM...