Voila exactement ce qu'il faut faire:
Skipping the Introductory Movies
One of the great annoyances of Assassin's Creed is that you can't skip through the startup movies/logos each time you begin the game. There is however a way you can remove them to speed up your startup time. Go to your \Program Files\Ubisoft\Assassin's Creed\Videos directory, and rename all the .bik files there, although I recommend leaving LoadingScreen.bik, otherwise you will face a long black screen on loadup with no indication of how far loading has progressed. Alternatively, instead of renaming the relevant .bik files, you can just create a new folder under the Video directory and move the movie files there. In any case once you do this, the next time you start the game it will reach the main menu much more quickly.