Are you shutting down all non-essential programs (especially anti-virus) before starting the game?
PhysX is one of the more common causes of crashing on startup; installing the latest version may help. You can also install the version that comes with the game (in the support folder); you may need to uninstall the current version and reboot first. If that gets the game to start, you should then be able to update to the latest version of PhysX.
[Solution] Game won't startGame won't start, I need help desperatelyDivinity II Crashing on Startup (avoided by using
DxWnd; the problem didn't reoccur after they switched to using a monitor, rather than a TV)