You cannot install updates from Windows Update, Microsoft Update, or by using Automatic Update after a repair install of Windows XP, a system restore, or after you install Windows XP SP3 immediately after a clean install of Windows XP SP2

CAUSE

This issue occurs because the Wups2.dll file that is included in the latest version of Windows Update is not installed correctly.

The registry entries that correspond to the Wups2.dll file are missing after the repair install of Windows XP. The release version of Windows XP does not contain the Windows Update software.

The registry entries that correspond to Windows Update are changed back to the Windows XP SP2 version if you did not restart the computer before you install Windows XP SP3. The registry entries for the Wups2.dll file are changed to pointing to the Wups.dll file that is included in the release version of Windows XP SP2.

Register the Wups2.dll file

To register the Wups2.dll file in Windows, follow these steps:

1. Stop the Automatic Updates service. To do this, follow these steps:
   1. Open the Command Prompt window. To do this, click Start, click Run, type cmd, and then click OK.
   2. At the command prompt, type the following command, and then press ENTER:
      net stop wuauserv
2. Register the Wups2.dll file. To do this, follow these steps:
   1. At the command prompt, type the following command, and then press ENTER:
      regsvr32 %windir%\system32\wups2.dll
      
      Note: For a computer that is running Windows XP Professional x64 Edition, type the following command, and then press ENTER:
      regsvr32 %windir%\syswow64\wups2.dll
   
   
   2. ClickOK if you receive a verification message.
3. Start the Automatic Updates service. To do this, type the following command at the command prompt, and then press ENTER:
   net start wuauserv
4. Exit the Command Prompt window. To do this, type exit at the command prompt, and then press ENTER.