First, I removed the game with CCleaner (like the programs who remove programs offert by windows)
After, I deleted the Divinity II folder cause there was still a folder. I found a folder in Appdata and in C:/Users/NAME/Documents/ (on vista)
Finally, I deleted all key with Regedit.
It still don't work.
I reinstalled the game by another way, right click on the DVD, Explore and run the setup. Still don't work to install it on the same disk. I installed it on a double layer DVD, but the game is really slow with low graphics
Any other solution to install it on my disk ?