After the installation of Windows XP Service Pack 3 (SP3), you might face some trouble with the Automatic Updates feature in Windows XP. In my case, I wasn’t able to install new updates.
An example of the error I got was:
Security Update for Windows XP with Windows Media Format Runtime 9.5 and 11 (KB941569) failed
The solution for this problem is re-registering some DLL-files. The steps below fix the problem if auto updates fail after a fresh install of Windows XP SP3
Open Start, Run, and run these commands, one by one:
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
You can also open Notepad, paste the above commands, save the file as RepairAU.bat, and run RepairAU.bat. This should save you approximaticaly 20 seconds of your lifetime :-)
Next time you open Windows Update / Microsoft Update, you should have no problems installing new updates.
Note: I surely believe Microsoft feels very sorry for this bug in SP3, and they really want to offer a hotfix for this problem, but since this hotfix would be offered by Automatic Updates, that won’t make much sense :-)