Problème résolu
"Just downloaded the catalyst 10.5: same problem, drivers and control center missing in the installer, even after a system clean up. The solution i found worked for me, maybe will do the same for you. So that's basically what you have to do: extract the installation files as always, then open the destination folder, C:\ATI\Support by default. You will see the folder that contains the 10.5 catalyst, open it than go to the folder named "Config". Inside this folder you will see the file "InstallManager.cfg". At the end of this file there is this string: "WorkaroundInstall=false". All you have to do is to change it by writing "true" instead of "false", don't forget to save. After i did this, both divers and control center magically reappeared in the installer, so i hope this will help you."
Finalement c'est ATI qui sait pas configurer ses drivers 