Open your Windows Explorer or My Computer, or Computer, whatever they call it, and navigate into your new C:\Ubisoft\Silent Hunter 4 folder, and double-click on SH4.exe there in order to start the game. That way, you're certain that you're running the correct executable. Also, don't attempt to run old saves from the first C:\Program Files install. Those usually won't function correctly for you, once you've started getting crashes. You usually have to start over from scratch when things like that happen... sorry. The vagaries of the old game...
