RISOLTO
In c:\windows\windowsupdate.log ho trovato l'errore 80004002 seguente:
2008-10-20 18:53:54:531 1560 634 Shutdwn Install at shutdown: found updates to install
2008-10-20 18:54:01:656 996 244 AU AU found 4 updates to install at shutdown.
2008-10-20 18:54:01:656 996 244 AU #############
2008-10-20 18:54:01:656 996 244 AU ## START ## AU: Install updates
2008-10-20 18:54:01:656 996 244 AU #########
2008-10-20 18:54:01:656 996 244 AU # Initiating install at shutdown
2008-10-20 18:54:01:656 996 244 AU # Approved updates = 4
2008-10-20 18:54:01:656 996 244 AU <<## SUBMITTED ## AU: Install updates / installing updates [CallId = {00FD1514-68E0-4296-BD41-BF5475EF3D47}]
2008-10-20 18:54:01:687 616 7a0 Misc =========== Logging initialized (build: 7.0.6000.381, tz: +0200) ===========
2008-10-20 18:54:01:687 616 7a0 Misc = Process: \??\C:\WINDOWS\system32\winlogon.exe
2008-10-20 18:54:01:687 616 7a0 Misc = Module: C:\WINDOWS\system32\wuaueng.dll
2008-10-20 18:54:01:687 616 7a0 Shutdwn WARNING: AU will install 4 updates.
2008-10-20 18:54:01:687 996 194 Agent *************
2008-10-20 18:54:01:687 996 194 Agent ** START ** Agent: Installing updates [CallerId = AutomaticUpdates]
2008-10-20 18:54:01:687 996 194 Agent *********
2008-10-20 18:54:01:687 996 194 Agent * Updates to install = 4
2008-10-20 18:54:02:609 996 194 Agent * Title = Strumento di rimozione malware di Windows – ottobre 2008 (KB890830)
2008-10-20 18:54:02:609 996 194 Agent * UpdateId = {424B1C8F-742A-4614-8012-1BB25B527706}.100
2008-10-20 18:54:02:609 996 194 Agent * Bundles 1 updates:
2008-10-20 18:54:02:609 996 194 Agent * {52236869-0291-4320-8B29-ED025121C58A}.100
2008-10-20 18:54:02:609 996 194 Agent * Title = Aggiornamento della protezione per Internet Explorer 7 in Windows XP (KB938127)
2008-10-20 18:54:02:609 996 194 Agent * UpdateId = {A2A1D3B3-C228-45AD-9175-566E7DD41DD1}.100
2008-10-20 18:54:02:609 996 194 Agent * Bundles 1 updates:
2008-10-20 18:54:02:609 996 194 Agent * {ECB0C269-9D84-4C3A-94A6-D8167951774B}.100
2008-10-20 18:54:02:609 996 194 Agent * Title = Pacchetto cumulativo di aggiornamenti della protezione per Internet Explorer 7 per Windows XP (KB956390)
2008-10-20 18:54:02:609 996 194 Agent * UpdateId = {41D1F3CB-6ABF-4AF8-BBB2-FD19E6501524}.102
2008-10-20 18:54:02:609 996 194 Agent * Bundles 1 updates:
2008-10-20 18:54:02:609 996 194 Agent * {FEF4C18D-C24F-46AB-9F09-C2AADA7483B8}.102
2008-10-20 18:54:02:609 996 194 Agent * Title = Aggiornamento cumulativo della protezione per ActiveX Killbits per Windows XP (KB956391)
2008-10-20 18:54:02:609 996 194 Agent * UpdateId = {25EE37D4-1EB2-4546-843F-AD0AC80BC14E}.104
2008-10-20 18:54:02:609 996 194 Agent * Bundles 1 updates:
2008-10-20 18:54:02:609 996 194 Agent * {08409719-975D-4CF4-9A9A-B2B16D838C79}.101
2008-10-20 18:54:05:625 384 744 Misc =========== Logging initialized (build: 7.0.6000.381, tz: +0200) ===========
2008-10-20 18:54:05:625 384 744 Misc = Process: C:\WINDOWS\system32\wuauclt.exe
2008-10-20 18:54:05:625 384 744 AUClnt FATAL: Error: 0x80004002. wuauclt handler: failed to spawn COM server
2008-10-20 18:54:05:640 996 194 Handler FATAL: 0x80004002: ERROR: Remote update handler container process created (PID: 384), but exited before signaling event
2008-10-20 18:54:05:640 996 94 AU >>## RESUMED ## AU: Installing update [UpdateId = {424B1C8F-742A-4614-8012-1BB25B527706}]
Facendo quindi una ricerca sul sito di supporto di Microsoft ho trovato la motivazione e la relativa soluzione qui
http://support.microsoft.com/kb/94314
Il problema si genera quando viene installato l'Sp3 su SO appena installato, prima di aver fatto almeno un riavvio (scenario 2).
Il file Wups2.dll non viene registrato e quindi provoca l'errore.
Soluzione perfettamente riuscita:
Start -> esegui -> cmd
Dal prompt comandi si digita
net stop wuauserv per interrompere il servizio update
Indi
regsvr32 %windir%\system32\wups2.dll per registrare il file correttamente
e per finire
net start wuauserv per riavviare il servizio update
L'errore si è completamente risolto