Did you try browsing to the ..\Divinity II - Developers Cut\bin folder and starting either the Divinity2.exe or Divinity2-debug.exe program files? You could try right clicking and running as administrator (that should bypass the making changes dialog, at least), or right click, select Properties, switch to the Compatibility tab and try a compatibility mode, etc.
Are you shutting down all non-essential programs (especially anti-virus) before starting the game? Something could be ok when the game is first run, but then after a restart decide it can 'optimize' something, or something needs to be blocked, etc. Alternately, something could be reset with the install, and updated after rebooting.
Did you install the game somewhere other than the Program Files path?
Browse to the folder below and rename the 'Profile' subfolder, to force the game to recreate the configuration files on startup. Alternately, you could try starting the game from a different Windows user account.
C:\Users\ %username% \AppData\Local\Divinity 2\
You may need to set Windows Explorer to show hidden files and folders (
Win 8).
