Hi,

I've bought the full BS pack, i've donwloaded BSDC twice but each time when i run the game i have the same problem a medium-sized window with a white bottom opens and closes immediately.

How can i fix it ?

Thx

You should always state your system specs and OS to let people help you.

Anyway, some things you can try are:
- Make sure that your Windows user account has Administrator privileges, then right-click game's shortcut and select "Run as Administrator".
- Try different compatibility modes: right-click the game's shortcut, go to Properties ->Compatibility and try different compatibility modes before attempting to launch the game again.
- Make sure DEP (Data Execution Prevention) is using its default setting.