I'm assuming you're talking about Silent Hill: Homecoming? If so, that game is available only via Steam, so if there are any patches, you will download them automatically via Steam.
It's a buggy game. It also does require some horsepower. I also had a problem where it was VERY slow and seemed to take forever to launch. I just reinstalled Steam and that cleared up all my problems. It still likes to dump me back to the desktop once in awhile.