ho risolto così :
Step 1. Open Notepad (or any text editor).
Step 2. Copy and paste the following command lines into the Notepad window
(the /s switch runs the commands silently, freeing you from having to press
Enter after each line):
regsvr32 /s wuapi.dll
regsvr32 /s wuaueng1.dll
regsvr32 /s wuaueng.dll
regsvr32 /s wucltui.dll
regsvr32 /s wups2.dll
regsvr32 /s wups.dll
regsvr32 /s wuweb.dll
Step 3. Save the file to your desktop, using a .bat or .cmd extension.
Step 4. Double-click the icon of the .bat or .cmd file.
Step 5. A command window will open, run the commands, and then close.
The next time you visit the Windows Update site, you should not have any
problem installing the latest patches.