WELCOME ABOARD!
The first problem might be Steam itself, though I'm pretty certain people do run it without too many problems. The second problem might be the platform you're running it on. Windows 7 and 8 don't like to let anything run under Program Files. It's a good idea to create a folder for the game inside the main 'C' folder and run it from there. I can't say much more since I'm still stuck with a nine-year-old single-core XP rig.
You might find some help in one of the many 'Running SH3 on Windows 7' threads, but they get tangled quickly so we can only hope someone with that experience will turn up here with the help you need. Knowing Subsim, it will happen.