Windows updates reports installation failed
Genuine Advantage Validation or Repaired installations of XP
The WGA engine may have been already installed but is not working properly.
Follow the next steps:
1. Download the ActiveX cab file from the following link and then save it to the Desktop.
http://download.microsoft.com/download/a/c/f/acfe4666-1faf-43fd-b6fb-19191521126d/LegitCheckControl.cab
Open the downloaded cab file and we will find the following three files:
GWFSPIDGen.dll
LegitCheckControl.dll
LegitCheckControl.inf
2. Click “Start”, click “Run”, type: “%windir%system32″ (without quotations) and press Enter. Copy the GWFSPIDGen.dll and LegitCheckControl.dll files into the opened system32 folder.
3. Click “Start”, click “Run”, type: “REGSVR32 LegitCheckControl.dll” (without the quotations) and press Enter. We will see a popup message state
this process succeeded.
4. Click “Start”, click “Run”, type: “inf” (without quotations) and press Enter. Copy the LegitCheckControl.inf file into the opened inf folder.
5. Right click on the copied LegitCheckControl.inf file in the inf folder, and then choose Install. The WGA engine will be installed automatically.
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.