Hi 63fisherman
I'm just replying letting you know that there are many members on this forum who will be able to help with your PC problem (unfortunately I'm not one of them) but I have SH3 installed from Steam using Win7 and 64bit without any hassle. Have you downloaded updates for your graphics card?
I hope you get it sorted as it's an excellent game with a nice learning curve.
All the best and good hunting