The default shortcut provided goes to Launcher.exe, a small program that accesses the Internet to provide details of updates and mods. Unfortunately Launcher on Vista takes 50% of CPU doing absolutely nothing and the main program fails to unload it, even when exited. It has to be turned off using Task Manager.
The solution is to create a shortcut to medieval2.exe.
Creative's sound driver for Vista remains buggy after 9 months, they seem to be unable to fix it. They did come up with an EAX patch, so that kind of works with Windows and more importantly with the range of games that don't have a 'plain vanilla' Soundblaster setting such as Medieval II. And then, knowing they had hordes of pissed off customers of Mongolian proportions, they charged $10 for it.
The game? It's fine, lots of epic battles.