Perfect solution, thanks for the information; I never believed I'll solve this problem without uninstalling the software and reinstalling same.
I haven'y any ACAD 2007/2008/2009 but I can imagine :
Launch REGEDIT (as a Local Admin)
HKEY_LOCAL_MACHINE \ SOFTWARE \ AUTODESK \ R17.0 \ ACAD-xxxxxxx
Then : CadManagerControl \ CommunicationCenter \ ...
EnableCommunicationCenter = 0