Windows Update - Solution if it stops working after XP repair mode
Microsoft recently introduced improvements to Windows Update and this appears to be working well, except in cases where a PC becomes unusable and the "repair mode" process is used. After restoring XP to an earlier state, there is a glitch between the old and new versions of Windows Update. The Windows Secrets article below is excellent and outlines steps that corporate users can employ now, until Microsoft corrects this issue. The links and key quotes from the article are noted below:
Stealth Windows update prevents XP repair Printable version
Repaired installations of XP can't be updated
The trouble occurs when users reinstall XP's system files using the repair capability found on genuine XP CD-ROMs. (The feature is not present on "Restore CDs.") The repair option, which is typically employed when XP for some reason becomes unbootable, rolls many aspects of XP back to a pristine state. It wipes out many updates and patches and sets Internet Explorer back to the version that originally shipped with the operating system.
However, after using the repair option from an XP CD-ROM, Windows Update now downloads and installs the new 7.0.600.381 executable files. Some WU executables aren't registered with the operating system, preventing Windows Update from working as intended. This, in turn, prevents Microsoft's 80 latest patches from installing — even if the patches successfully downloaded to the PC.
Manually registering files solves the problem
If you find that Windows Update refuses to install most patches, you can register its missing DLLs yourself. This can be accomplished by manually entering seven commands (shown in Step 2, below) at a command prompt. If you need to run the fix on multiple machines, it's easiest to use a batch file, as Steps 1 through 5 explain:
Step 1. Open Notepad (or any text editor).
Step 2. Copy and paste the following command lines into the Notepad window (the /s switch runs the commands silently, freeing you from having to press Enter after each line):
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
Step 3. Save the file to your desktop, using a .bat or .cmd extension.
Step 4. Double-click the icon of the .bat or .cmd file.
Step 5. A command window will open, run the commands, and then close.
The next time you visit the Windows Update site, you should not have any problem installing the latest patches.