I did it !

It is very simple

SQL 2005 installation has removed key from

HKEY_CLASSES_ROOT\CLSID\00100100-1816-11D0-8EF5-00AA0062C58F

I placed them back, and it works ! (Enterprise Manager)

Windows Registry Editor Version 5.00

[HKEY_CLASSES_ROOT\CLSID\{00100100-1816-11d0-8EF5-00AA0062C58F}]

@="Microsoft SQL Enterprise Manager SnapIn"

[HKEY_CLASSES_ROOT\CLSID\{00100100-1816-11d0-8EF5-00AA0062C58F}\InProcServer32]

@="C:\\Program Files\\Microsoft SQL Server\\80\\Tools\\Binn\\sqlmmc.dll"

"ThreadingModel"="Both"

[HKEY_CLASSES_ROOT\CLSID\{00100100-1816-11d0-8EF5-00AA0062C58F}\ProgID]

@="SQLMMC.1"

[HKEY_CLASSES_ROOT\CLSID\{00100100-1816-11d0-8EF5-00AA0062C58F}\VersionIndependentProgID]

@="SQLMMC"