How to Install Failed Microsoft Updates
If your Windows computer encounters an update that refuses to install properly, there is little support available that will give you a good answer as to why it decided to fail. In cases where you attempt to reinstall it multiple times (it will automatically be put back in your installation queue) and it keeps failing, you will need to remove and reinstall all of your Windows updates for it to install properly. After removing the folder that contains all of your Windows updates, all of the updates will be put back in your installation queue and should install properly.
Open the Windows Services utility by going to the "Start" menu, selecting "Run," typing "services.msc" into the search box and then clicking "OK." In Windows 7/Vista, type it into the "Start Search" box in the "Start" menu and hit "Enter."
Click on the "Name" field to sort the list of services by name. Scroll down the list to "Automatic Updates" ("Windows Update" in Windows 7/Vista), right-click on it and select "Stop." Right-click on "Background Intelligent Transfer Service" (directly underneath "Automatic Updates" in Windows XP) and select "Stop."
Go back to the Run tool in the Start menu (if it does not appear in your Start menu, press the "Windows" key + "R" to open it). Copy and paste "C:\Windows\SoftwareDistribution," click "OK" and then delete all the contents of the folder (press and hold the "Ctrl" key, click to select each file, and then press the "Delete" key on your keyboard).
Close the folder and go back to the Windows Services utility. Right-click on the two services you stopped ("Automatic Updates"/"Windows Update" and "Background Intelligent Transfer Service") and select "Start."
Open Windows Update by going to the Run tool, typing "%SystemRoot%\system32\wuapp.exe" into the search box ("%SystemRoot%\system32\wupdmgr.exe" in Windows XP) and then clicking "OK."
Click "Check for updates." Windows will now find all of your updates and prompt you to download and install them.