I have recently reinstalled XP on my laptop and everything worked like a charm. I have downloaded 95% of windows updates including SP3 and .NET updates.
BUT suddenly windows updates stopped working. This means also that Windows Defender could not update as well.
The error that I received was 0×80004002 and in c:\windows\windowsupdate.log I have found that this error was explained with text: Error: 0×80004002. wuauclt handler: failed to spawn COM server.
Some Googling helped and I have found that .dll files that were used by Windows Update were not registered correctly. I think that update of Windows Installer caused this mess because I have used Windows Update after reinstallation until one point where I was trying to download 1 or 2 remaining updates.
Easy fix for this is:
1. Start->Run->cmd
2. paste following and type enter
regsvr32.exe c:\windows\system32\wuweb.dll
regsvr32.exe c:\windows\system32\wups2.dll
regsvr32.exe c:\windows\system32\wups.dll
regsvr32.exe c:\windows\system32\wucltui.dll
regsvr32.exe c:\windows\system32\wuaueng1.dll
regsvr32.exe c:\windows\system32\wuaueng.dll
regsvr32.exe c:\windows\system32\wuapi.dll
3. Update