Hello Olivier,
Thank you for your reply.
I would suggest you to perform in-place upgrade and check the issue.
Refer this article:
How to Perform an In-Place Upgrade on Windows Vista, Windows 7, Windows Server 2008 & Windows Server 2008 R2
https://support.microsoft.com/en-us/kb/2255099
Note: I highly recommend backing up all of your important files and folders onto an external storage device before attempting any type of OS repair or upgrade.
Thank you