Windows XP Service Pack 3 can break the automatic updates under certain circumstances due to a DLL that may not be registered. If the update system starts to fail with messages like “updates not installed”, do the following:
- Stop the update service:
net stop wuauserv
- Register the DLL:
regsvr32 %windir%\system32\wups2.dll
- Restart the update service:
net start wuauserv
The update service should work again.